Donate
Independent, objective, nonpartisan research

EP 706EHEP

Authors

EP 706EHEP

Tagged with:

Publication PDFs

Database

This is the content currently stored in the post and postmeta tables.

View live version

object(Timber\Post)#3711 (44) { ["ImageClass"]=> string(12) "Timber\Image" ["PostClass"]=> string(11) "Timber\Post" ["TermClass"]=> string(11) "Timber\Term" ["object_type"]=> string(4) "post" ["custom"]=> array(5) { ["_wp_attached_file"]=> string(14) "EP_706EHEP.pdf" ["wpmf_size"]=> string(7) "1168585" ["wpmf_filetype"]=> string(3) "pdf" ["wpmf_order"]=> string(1) "0" ["searchwp_content"]=> string(85678) "Public Policy Institute of California CEP California Economic Policy Ellen Hanak and David Neumark, editors Volume 2, Number 2 n July 2006 Lawns and Water Demand in California By Ellen Hanak and Matthew Davis California Economic Policy is a quarterly series analyzing and discussing policy issues affecting the California economy. SUMMARY O ver the next 25 years, California’s population is expected to grow by some 11 million residents, with over half of this growth occurring in the hotter inland counties. This shift raises the prospect of substantial increases in urban water demand, especially for outdoor uses, because landscaping typically accounts for at least half of all residential water use in inland areas. Because water demand growth poses both financial and environmental challenges, many water utilities are now launching conservation programs to curb water use outdoors. In this issue of CEP, we examine the role of residential land use in the demand for water outdoors, with a focus on the water needs of cool-season turf grass lawns. We also explore the savings potential of some key water conservation tools. Drawing on detailed residential housing data, we find that outdoor water needs for typical residential lots are likely to be more than two to three times higher in inland areas than along the coast. Although climate plays a role in this difference, residential land use patterns are far more important. Single-family homes, which typically use about twice as much landscaping water as multifamily units, make up a much larger share of inland housing. Inland areas also generally have larger lots, including a higher proportion of “ranchettes” (i.e., lots between one and 20 acres). Recent housing trends suggest some attenuation of these differences, with the rise of denser single-family tract developments in the Central Valley and the Inland Empire. But in contrast to the coast, where there has been a surge in multifamily housing since 2000, the inland region has seen multifamily homes continue to fall as a share of total housing. Recent conservation efforts have aimed to lower outdoor water use by improving the effi- ciency of landscape irrigation and replacing some lawns with less thirsty plants. Field studies suggest that both strategies offer considerable potential for saving water. At the state level, there has also been renewed attention to the role of water rates, which often fail to provide residents with correct signals about the scarcity of water resources. Conservation-oriented water rates can play an important role in both new and existing neighborhoods. Our analysis also suggests that improved irrigation technologies may be cost effective in many parts of the state, even when water rates are relatively low. By contrast, “cash for grass” programs, which give homeowners rebates for replacing turf with drought-tolerant plants, are likely to pay off only if the new landscapes also California Economic Policy Lawns and Water Demand in California lead to substantial savings in garden supplies and labor. Promotional strategies to implement conservation include public education and outreach, customer rebates, and regulatory restrictions on landscaping options. Whether education and outreach will be sufficient to encourage new development to be “water smart,” or whether regulatory solutions are required, is still an open question. Introduction Without efforts to reduce per capita water use, California faces significant increases in urban water demand over the coming decades—a prospect that poses both environmental and financial challenges. Lawns are one of the biggest culprits. Outdoor water use often accounts for half or more of all residential water demand, especially in the hotter inland areas where population growth is now fastest. California’s inland counties are expected to accommodate over half of the 11.3 million new California residents anticipated over the next 25 years. In addition, an increasing share of growth is occurring in warmer inland areas of coastal counties.1 Recognizing the water demand that this population growth will bring, water utilities are paying more attention to urban water conservation than ever before. Whereas conservation efforts during the 1990s focused mainly on indoor uses, the focus is now shifting to the outdoors. The policy toolkit includes a host of incentives and technological fixes to encourage residents to water their yards more efficiently and to landscape with low-water plants. To help spearhead these efforts, the legislature recently called for the creation of a Landscape Task Force, composed of stakeholders from the water and landscaping sectors, to evaluate and recommend proposals for improving the efficiency of water use in new and existing urban irrigated landscapes in California. Landscape choices are considered key because Californians—like their neighbors in other semiarid western states—have tended to use plants more suited to humid climates. The typical California lawn, a cool-season turf grass, can require several times more water than native plants. Inefficient watering systems, such as incorrectly timed automatic sprinklers, can significantly compound the problem, creating overwatered lawns and excess water spillage.2 In addition to the resource costs associated with water waste, overwatering generates polluted run-off, which damages rivers, lakes, and coastal waters. 2 P u b l ic P o l ic y I n stit u te of C a l ifor n ia California Economic Policy Lawns and Water Demand in California Land use patterns also matter. Denser development—with more multifamily homes and smaller single-family lots—is typically also more water smart. On a per household basis, multifamily homes use half as much water outdoors as do single-family homes. Among single-family homes, those with larger lots typically use more water for landscaping. This edition of CEP looks at a range of issues related to residential outdoor water use. Drawing on detailed residential housing data, we first assess whether housing patterns are reinforcing or extenuating the pressures posed by California’s demographic shift inland. To determine patterns in outdoor water use, we examine differences across regions and over time in the composition of the housing stock (in particular, the share of multifamily homes) and in the size of single-family lots. We use the reference evapotranspiration rate— a measure of the amount of water required to maintain turf grass in different climatic zones— to estimate the water needs of typical yards across regions. Finally, we assess the potential for key elements in the conservation policy toolkit—including water pricing and various programs to improve irrigation efficiency and encourage the use of lowwater plants—to reduce outdoor water use in different parts of the state. human water use in the state in 2000. California’s cities The urban share has been growing over time; in 1980, it accounted for only 14 percent of the total (Department of Water Resources, 1983). This increase and suburbs used approximately 8.9 million acre-feet of water in 2000, or about 232 gallons is not simply the result of pop- per person per day. ulation growth. Per capita use rose steadily throughout the latter half of the 20th century, with declines setting in only during the 1990s (Figure 1). Average urban per capita use was 185 gallons per day in 1960, 20 percent lower than in 2000. The growth in per capita use probably reflects several factors. One is rising incomes, which tend to increase water demand, in part because of greater demand for water-using appliances (Baumann, Boland, and Hanemann, 1997). A second is resi- dential lot sizes, which, as we shall see, increased over much of this period. A third is the faster rate of population growth in hotter inland areas, where water use is considerably higher. In 2000, inland water use averaged 355 gpcd compared to 195 gpcd along the coast. Even with continued efforts in conservation, total urban water use could grow significantly over Water Use and Population Growth in California According to the Department of Water Resources (DWR) 2005 update of the California Water Plan, California’s cities and suburbs used approximately 8.9 million acre-feet (maf) of water in 2000, or about 232 gallons per capita per day (gpcd).3 This total—often known as the “urban” water demand—includes all residential, commercial, governmental, and industrial uses, with residential uses constituting about twothirds of the whole, or 5.8 maf. In the same year, California’s farmers irrigated an estimated 9.6 million acres of cropland with 34.2 maf of water. Thus, urban uses accounted for 20 percent of total Gallons per capita per day Figure 1. Urban Water Use in California, 1960 to 2000 (gpcd) 400 California Coastal Inland 350 300 250 200 150 100 1960 1967 1972 1980 1985 1990 1995 2000 Sources: Department of Water Resources (1966, 1970, 1974, 1983, 1987, 1994b, 1998, 2005). Notes: “Coastal” includes the North Coast, San Francisco Bay, Central Coast, and South Coast hydrologic regions. “Inland” includes the Sacramento River, San Joaquin River, Tulare Basin, North Lahontan, South Lahontan, and Colorado River hydrologic regions. Although the individual regional classi cations varied somewhat in earlier periods, the broad distinction between coastal and inland is fairly consistent over time. 3P u b l ic P o l ic y I n stit u te of C a l ifor n ia California Economic Policy Lawns and Water Demand in California the coming decades. The California Water Plan’s “current trends” scenario anticipates demand growth by 3.0 maf between 2000 and 2030, despite a projected modest decrease in per capita use, from 232 to 221 gpcd. Southern California’s urban utili- ties will face additional needs because of require- ments to reduce their use of Colorado River water by 0.8 maf. Such levels of demand growth pose consider- able challenges for California’s urban water utili- ties. Most new sources of water are relatively costly, and many options pose risks to the environment because of their effects on wildlife habitat. In prin- ciple, a good deal of urban demand growth could be accommodated by transfers of agricultural water rights to urban users, because agricultural water use is expected to decline as a result of various market forces, includ- Although a majority of ing land development (Depart- California’s population still lives in the two main metropolitan coastal regions . . . forecasts ment of Water Resources, 2005). In practice, transfers are likely to account for only a portion of urban needs because of institutional and logistical constraints suggest that some of the biggest growth pressures in the coming decades will be in hotter (Hanak, 2003). Among other alternatives, the Plan highlights urban conservation as one of the single largest sources of costeffective “new” water to support inland areas. growth.4 Growth Patterns and Outdoor Water Use Because water meters do not generally track indoor and outdoor uses separately, the share of urban water used outdoors can only be estimated. The 2005 California Water Plan estimates that the residential sector used roughly 2.3 maf outdoors in 2000, or 42 percent of total residential demand. Parks, golf courses, and other “large landscapes” used another 0.7 maf.5 (The Plan did not separately estimate outdoor uses for commercial and industrial customers.) The Plan’s estimates for outdoor residential use may be on the low side. One study of a crosssection of 12 U.S. cities found an average outdoor rate of 58 percent (Mayer et al., 1999). California’s Landscape Task Force concluded that outdoor use constitutes about half of residential demand in the state (California Urban Water Conservation Council, 2005). This share can be much lower in milder coastal zones and much higher in hot, dry, desert areas. The water provider for the Las Vegas Valley, located in the Mojave Desert, estimates that roughly 70 percent of residential demand goes to outdoor irrigation.6 Officials in Riverside County estimate that 80 percent of residential water in the Coachella Valley—an area with a similar climate— is used outdoors (Bowles, 2005). Although a majority of California’s population still lives in the two main metropolitan coastal regions—the Los Angeles Basin and the San Francisco Bay Area—forecasts suggest that some of the biggest growth pressures in the coming decades will be in hotter inland areas (Table 1). California’s population is projected to grow by 11.3 million people between 2005 and 2030, and over half of that growth will occur inland—the Sacramento Metro region, the San Joaquin Valley, and the Inland Empire. Residential Lot and Yard Sizes Outdoor water use tends to rise with singlefamily lot sizes, because larger properties have larger yards. County assessor records make it possible to measure lot sizes for singlefamily homes in most of the counties in our main metropolitan regions (for details, see the web-only appendix, http://www.ppic.org/content/other/706EHEP_ web_only_appendix.pdf). We define “yards” as lot size minus the building footprint. Because it is likely that residents with very large lots water a smaller portion of their yards, we have broken these data into small lots (one acre or less) and large lots (between one and 20 acres). Figure 2 presents the cumulative average lot sizes by region for single-family residences 4 P u b l ic P o l ic y I n stit u te of C a l ifor n ia California Economic Policy Lawns and Water Demand in California Table 1. Projected Population Growth in California Regions, 2005–2030 (millions) Region San Francisco Bay Area South Coast Sacramento Metro region San Joaquin Valley Inland Empire Rest of state California Counties Alameda, Contra Costa, Marin, Napa, San Francisco, San Mateo, Santa Clara, Solano, Sonoma Los Angeles, Orange, San Diego, Ventura El Dorado, Placer, Sacramento, Yolo Merced, San Joaquin, Stanislaus, Fresno, Kern, Kings, Madera, Tulare Riverside, San Bernardino Alpine, Amador, Butte, Calaveras, Colusa, Del Norte, Glenn, Humboldt, Imperial, Inyo, Lake, Lassen, Mariposa, Mendocino, Modoc, Mono, Monterey, Nevada, Plumas, San Benito, San Luis Obispo, Santa Barbara, Santa Cruz, Shasta, Sierra, Siskiyou, Sutter, Tehama, Trinity, Tuolumne, Yuba Population, 2005 7.10 17.15 2.04 3.73 3.82 2.98 36.81 Projected Growth, 2005–2030 2.08 2.74 1.37 2.19 2.12 0.80 11.30 Sources: Department of Finance (2004, 2005). Percent of Projected Growth 18.4 24.3 12.1 19.4 18.8 7.1 100 on small lots.7 The San Joaquin Valley is split into two regions to isolate the effects of growth pressures that link its northern end to the Bay Area and its southern end to the population centers in Southern California. As expected, lot sizes are smallest in the region with the highest land prices, the San Francisco Bay Area (7,697 square feet), and they are generally largest in the inland regions, notably the Inland Empire (10,176 square feet) and the Sacramento Metro region (9,515 square feet). What is surprising, however, is the steady upward trend in coastal lot sizes, particularly in Los Angeles and San Diego Counties. Lots in the South Coast (9,076 square feet) are now larger, on average, than those in the northern San Joaquin Valley (8,416 square feet) and nearly as large as those in the southern San Joaquin Valley (9,056 square feet). Because the proportion of homes with more than one story has been on the rise, there has been Square feet Figure 2. Cumulative Average Small Single-Family Lot Sizes by Region 12,000 Inland Empire San Joaquin Valley, south Sacramento Metro San Joaquin Valley, north Southern California Coast San Francisco Bay Area 10,000 8,000 6,000 4,000 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 Source: Authors’ calculations, using county assessor records through 2002. Notes: Data include lots of one acre or less. One acre equals 43,560 square feet. 2000 5P u b l ic P o l ic y I n stit u te of C a l ifor n ia California Economic Policy Lawns and Water Demand in California Despite the recent relatively little increase in average building footprints (estimated as policy attention to denser land use—often known as “smart growth”— California actually built the building size divided by the number of stories), even though home sizes have been steadily increasing.8 Thus, the general patterns for yard sizes are simi- many more multifamily lar to those shown in Figure 2. homes in the 1960s and 1970s than it does today. Meanwhile, lots between one and 20 acres, often called ranchettes, remain an impor- tant component of California’s residential landscape (Figure 3). The shares of these lots are lowest in the two coastal regions and also relatively low in the northern San Joa- quin Valley, which appears increasingly influ- enced by Bay Area housing patterns. Ranchettes average around three acres in size but somewhat higher in the Sacramento region (4.7 acres). They are particularly prominent in some counties— Napa and Sonoma in the Bay Area, El Dorado and Placer in the Sacramento Metro region, Kern in the southern San Joaquin Valley, and San Diego in the South Coast.9 The share of multifamily housing is another important factor in the outdoor water use equa- tion. Because they share common outdoor space, Share (%) Figure 3. Cumulative Share of Large Single-Family Lots by Region 20 Inland Empire San Joaquin Valley, south Southern California Coast Sacramento Metro San Joaquin Valley, north San Francisco Bay Area 15 10 5 0 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 Source: Authors’ calculations, using county assessor records through 2002. Note: Data include lots between one and 20 acres. 2000 multifamily homes use considerably less water outdoors than do single-family residences. Despite the recent policy attention to denser land use—often known as “smart growth”—California actually built many more multifamily homes in the 1960s and 1970s than it does today (Figure 4). Although the share of multifamily housing has increased since 2000, this is mainly a coastal phenomenon. In the hotter inland regions, the overall shares are much lower (Figure 5). As we shall see, these housing trends have a marked effect on outdoor water needs in different parts of the state. Climate Zones and Housing Trends Because hotter climates increase water needs for any given lot size, we reclassified the housing data by climatic zone. These zones are based on evapotranspiration rates for the typical California lawn. Evapotranspiration (ET) is the rate at which plants lose water through evaporation from soil and plant surfaces and transpiration through plant canopies. “Reference evapotranspiration” (ET0) rates provide a measure of the water needed by cool-season turf grass. Thus, ET0 rates give a measure of the baseline water needs of a typical California lawn in different parts of the state. We assigned each Census tract to one of 18 ET0 zones, using maps provided by DWR. For purposes of presentation, we consolidated the 18 zones into four “superzones”: Coastal, Inner Coastal, Central, and Desert (Figure 6).10 The differences across zones are significant. In the Coastal zone, a square foot of cool-season turf grass will require 28 gallons of water or less per year. In the Desert zone, the same patch of grass will need 37 gallons of water or more. The differences are even more pronounced during the dry summer months, when irrigation needs are highest (Figure 6). These evapotranspiration zones provide a much finer breakdown of climatic differences than do regional and county boundaries. Whereas climates 6 P u b l ic P o l ic y I n stit u te of C a l ifor n ia California Economic Policy Lawns and Water Demand in California Share (%) in some regions appear relatively homogeneous (for instance, the Sacramento Metro region and the northern San Joaquin Valley fall entirely within the Central zone), other areas display a great deal of variation. Los Angeles County, for example, spans the entire spectrum from mild coastal to harsh desert climates (for details on individual counties, see the web-only appendix, http://www.ppic.org/content/ other/706EHEP_web_only_appendix.pdf). As of the 2000 Census, 33 percent of the state’s population resided in the Coastal zone, 43 percent in the Inner Coastal zone, 19 percent in the Central zone, and 4 percent in the Desert zone. However, housing production in the Central and Desert zones is growing fast (Figure 7). Nearly 39 percent of the units built in the 1990s were in these two zones, up from 32 percent in the 1980s and just 26 percent in the 1970s. Housing production in the Central zone has now eclipsed production in the Coastal zone. Single-family lots are 60 percent larger in the Desert zone than in the Coastal zone, and large lots are still far more preponderant in the hot inland zones. In addition, the share of multifamily homes recorded by the 2000 Census reads, in inverse order of climate conditions: Coastal (40.1%), Inner Coastal (33.6%), Central (21.1%), and Desert (20.4%). Implications for Outdoor Water Demand Clearly, land use differences across climatic zones appear to be reinforcing the pressures of the demographic shift inland. Despite some signs of inland densification—declines both in lot sizes and in the share of ranchettes—inland areas have lower shares of multifamily homes, higher shares of ranchettes, and higher average lot sizes than does the coast. What do these land use trends mean for outdoor water use? Theoretical Water Needs To get a sense for outdoor water demand, we estimated the average water requirements for cool- Number Figure 4. Statewide Trends in Multifamily Construction, 1940–2004 120,000 100,000 80,000 Multifamily homes built per year (left axis) Share of multifamily homes (right axis) 58% 47% 70 60 50 60,000 30% 40,000 19% 30% 23% 40 28% 30 20 20,000 10 00 1940–50 1950–60 1960–70 1970–80 1980–90 1990–2000 2000–04 Sources: Authors’ calculations, using data from the Census (1940–2000) (changes in housing stock) and the Construction Industry Research Board (2004) (housing permits). Notes: The multifamily category includes structures with two or more residential units; it excludes both detached and undetached single-family homes. Data exclude “other” housing categories, such as mobile homes and boats. Figure 5. Regional Shares of Multifamily Homes in Housing Stock and New Construction 50 44 40 35 30 20 10 47 38 Housing stock, early 2000 New construction, 2000–04 19 14 20 9 24 18 0 Bay Area South Coast Inland Empire San Joaquin Sacramento Valley Metro Source: Authors’ calculations, using the 2000 Census (stock) and Construction Industry Research Board (permits). Share (%) season turf grass, our ET0 crop. Table 2 provides these estimates for small single-family lots by region and by ET0 superzone. We assume that households irrigate 35 percent of their yard, with the remainder covered either in hardscape or in non-irrigated landscape.11 Across regions, this amounts to an average irrigated area in the range of 2,000 to 3,600 square feet. Average water requirements are obtained by multiplying this area by average ET0 rates.12 7P u b l ic P o l ic y I n stit u te of C a l ifor n ia California Economic Policy Lawns and Water Demand in California Number Figure 6. Evapotranspiration “Superzones” Summer water requirements (turf grass) (monthly gallons per square foot) Coastal (2.6–3.6) Inner Coastal (3.7–4.2) Central (4.3–4.7) Desert (5.0–5.4) Figure 7. Units Built by Decade by ET0 Superzone 1,200,000 Coastal Inner Coastal Central 1,000,000 800,000 600,000 400,000 200,000 0 1940 1950 1960 1970 1980 Source: Authors’ calculations based on the 2000 Census. Note: Includes all California counties. Desert 1990 2000 Because of larger lot sizes and drier climates, the amount of water lost through evapotranspiration from a typical grass lawn is much greater in California’s inland areas. In the Coastal zone, a typical single-family lawn requires 0.17 acre-feet per year, whereas its Desert zone counterpart needs nearly three times as much. With some additional assumptions, we can apply this same framework to the entire housing stock, incorporating ranchettes and multifamily lots (Table 3). For ranchettes, we assume only 10 percent irrigated landscaping, corresponding to an average area of roughly one-quarter of an acre.13 For multifamily homes, we assume that outdoor water use is half the single-family average.14 These estimates imply that California households irrigated a total of just under 633,000 acres in 2000.15 For the most part, incorporating these additional housing stock characteristics exacerbates the differences in regional water needs described in Table 2. Water needs decrease in the Bay Area and the South Coast and in the corresponding climatic zones (Coastal and Inner Coastal)—a benefit of the high share of multifamily homes. Elsewhere, the effect of large lots dominates. This effect is most striking for the Sacramento Metro region, where ranchettes are most common: The average household’s outdoor water needs increase by 60 percent. For the Central and Desert zones as a whole, these needs increase by 20 to 30 percent. Water requirements in these zones are more than two to three times greater than on the coast. Because climate and land use are working in the same direction, it is useful to see how much each factor contributes to these regional differences. Figure 8 compares estimated water needs in inland zones with the water needs these zones would face if they shared the more compact housing patterns of the coast. Actual land use patterns account for a substantially greater share of the additional water needs than climate does. In the Central and Desert zones, land use—not climate—is the clear driver, accounting for four-fifths of the total increase relative to the Coastal zone. Recent changes in land use may be shifting outdoor water needs. To track this trend, we compared the water needs of homes built between 1991 and 2000 with the needs of the 1990 housing stock. Figure 9 shows these comparisons, with new housing needs expressed as a percentage of the needs of homes already built by 1990. To isolate the effects of lot size and composition, we applied the ET0 rates for older homes to the new housing. For single-family homes of one acre or less, denser tract development in the four inland regions 8 P u b l ic P o l ic y I n stit u te of C a l ifor n ia California Economic Policy Lawns and Water Demand in California Table 2. Average Water Requirements of Turf Grass for Small Single-Family Lots Region Yard Size (square feet) Weighted Average ET0 (inches/year) Annual Water Requirements (acre-feet) San Francisco Bay Area 6,308 45.9 0.19 South Coast 7,623 49.8 0.25 San Joaquin Valley, north 7,060 54.4 0.26 San Joaquin Valley, south 7,711 56.2 0.29 Sacramento Metro region 8,129 56.8 0.31 Inland Empire 8,858 56.2 0.33 ET0 zone Coastal 6,019 42.6 0.17 Inner Coastal 7,930 51.9 0.28 Central 7,687 56.0 0.29 Desert 10,349 66.7 0.46 % Increase over Region with Lowest Need — 31 33 50 59 72 — 60 68 169 Table 3. Average Water Requirements of Turf Grass for Residential Lots Small Single-Family Lots Large Single-Family Lots Multifamily Lots Region % of Average % of Average All Yard Size All Yard Size Lots (square feet) Lots (square feet) % of All Lots San Francisco Bay Area 61.2 6,308 2.8 139,855 36.0 South Coast 59.1 7,623 1.6 119,824 39.3 San Joaquin Valley, north 76.1 7,060 3.7 134,766 20.2 San Joaquin Valley, south 67.8 7,711 7.4 152,849 24.8 Sacramento Metro region 63.8 8,129 11.5 203,920 24.7 Inland Empire 74.6 8,858 4.7 127,035 20.7 ET0 zone Coastal 58.7 6,019 1.1 127,382 40.1 Inner Coastal 64.4 7,930 2.0 111,147 33.6 Central 71.4 7,687 7.5 175,058 21.1 Desert 70.0 10,349 9.6 144,556 20.4 Average Annual Water Requirements Acre-Feet per Household % Increase over Region with Lowest Need 0.19 — 0.22 16 0.27 46 0.36 89 0.50 165 0.35 85 0.15 — 0.25 67 0.38 158 0.55 276 9P u b l ic P o l ic y I n stit u te of C a l ifor n ia California Economic Policy Lawns and Water Demand in California Annual water needs per household (acre-feet) Water needs of 1990 housing stock = 100 Figure 8. Effects of Climate and Land Use on Outdoor Water Needs of Turf Grass 0.60 Water needs with coastal land use Incremental needs related to actual land use 0.50 0.40 0.30 0.20 0.10 0.00 Coastal Inner Coastal Central Desert Figure 9. Comparison of Outdoor Water Needs for Homes Built During the 1990s and Older Homes 180 160 140 120 100 100 107 80 163 141 Small single-family lots All residential lots 102 90 93 87 85 91 122 91 60 40 20 0 Bay Area South Coast San Joaquin San Joaquin Inland Sacramento Valley, north Valley, south Empire Metro Note: Calculations use 1990 average evapotranspiration rates to control for the effect of changes in the location of new housing. has reduced landscape water needs for new homes by 9 to 15 percent compared to the older housing stock. The opposite is true in the South Coast, where single-family lots have been getting larger. The picture changes somewhat when we take into account all types of new housing combined. Some of the inland savings disappear, and water needs increase substantially in the South Coast and in the Sacramento Metro region. One factor is the declining share in new construction of multifam- ily housing in the 1990s, which occurred in every region. But an even bigger factor is the growing role of large lots. They rose slightly as a share of all housing in three regions (Sacramento Metro, South Coast, and the Bay Area), and they increased in average size everywhere. For the South Coast, the overall result is a profile of new housing with potential landscape water needs over 60 percent above the level in 1990. In the Bay Area and the South Coast, these needs have also increased somewhat because newer housing has located in warmer areas.16 These trends have reduced some of the differences in water needs between coastal and inland regions. Actual Water Needs Of course, these figures provide only a “guesstimate” of households’ actual outdoor water use. In practice, there is considerable variation in the proportion of yards that are watered, and not everyone plants only cool-season turf grass, our baseline crop.17 Moreover, irrigation practices can differ widely. The ET0 rates for turf grass allow for a lush, thick lawn, several inches high. In practice, experts assume that residential lawns can get by with about 80 percent of the ET0 requirements.18 However, the ET0 rates also assume that no water is wasted, either in making the ground soggy or in spilling onto sidewalks and streets. Such wastage results in a level of irrigation efficiency—the share of water actually used by the plant—below 100 percent. Many residences and businesses still fall well below the existing statewide standard for landscape irrigation efficiency of 62.5 percent. The amount of water a plant actually needs (sometimes known as the “ET adjustment factor”) can be summarized in this fashion: ET adjustment factor = plant’s ET requirement irrigation efficiency rate Thus, a residential lawn with an 80 percent ET requirement, irrigated at 80 percent efficiency, needs 100 percent of its baseline water needs (the ET0). If irrigation efficiency is lower, the actual water 10 P u b l ic P o l ic y I n stit u te of C a l ifor n ia California Economic Policy Lawns and Water Demand in California Table 4. Landscape Water Needs with Different Plant Types and Irrigation Efficiencies Average Plant ET Requirement Irrigation Efficiency 50% 62% 70% 80% High Water (80%) 160 129 114 100 Medium Water (50%) 100 81 71 63 Low Water (20%) 40 32 29 25 50% High 50% Medium (65%) 130 105 93 81 Note: Numbers are expressed as a percentage of reference evapotranspiration. a1/3:1/3:1/3 denotes a mix of one-third each high-, medium-, and low-water-using plants. 1/3:1/3:1/3a (50%) 100 80 71 62 needed is greater than 100 percent. If it is higher, or if the plant mix is less thirsty, the actual water needed falls below 100 percent. Table 4 summarizes this relationship for some benchmark plant types and irrigation efficiency rates. Cool-season turf is a typical high-water-using plant. (Warm-season turf grass, still not very common in California, has an ET requirement of 60 percent.) Various landscape alternatives, including shrubs and trees, fall into the medium category, and many native species are low water users. A conventional residential mix might be half cool-season grass and half trees and shrubs, for an overall ET requirement of 65 percent.19 Using California’s irrigation efficiency standard of 62.5 percent, such a yard would require 105 percent of the ET0 shown in Tables 2 and 3. We estimate that the average for California yards in 2000 was in the range of 106 to 127 percent of the ET0.20 In a normal year, rainfall during the cooler winter months can generally cover about a quarter of these needs, and the balance must be made up with irrigation. In dry years, which are no stranger to California, landscape water needs are typically higher. Because supplies are also scarcer in such times, droughts often lead utilities to impose outdoor watering restrictions. Looking ahead, there is a strong possibility that climate warming will increase plant water needs in California—particularly in the hotter inland areas, where average temperatures are predicted to rise considerably (Hayhoe et al., 2004). Climate change is also expected to put greater pressures on water supplies by reducing the amount of water stored in the Sierra Nevada snowpack.21 These shifts will Smart growth land use mixes that achieve higher density can truly be water smart. However, most approaches to outdoor conservation raise the importance of efforts to curb outdoor water use. focus on ways to reduce water use with existing land use patterns. Conservation Strategies As the preceding analysis makes clear, land use patterns can have a tremendous effect on the potential outdoor water needs of the residential sector. Smart growth land use mixes that achieve higher density can truly be water smart. However, most approaches to outdoor conservation focus on ways to reduce water use with existing land use patterns. The following four strategies provide different paths toward water-smart yard mainte- nance and greater outdoor water conservation. Water Pricing One overarching tool that is gaining renewed attention is water pricing. There are four general kinds of rate structures: flat, declining block, uniform, and 11P u b l ic P o l ic y I n stit u te of C a l ifor n ia California Economic Policy Lawns and Water Demand in California increasing block. Flat water rates—which do not vary by the amount of water used—are still com- mon in the Central Valley, much of which remains unmetered. Declining block rates, which essentially offer a bulk discount to heavy water users, are now rare. Most residential lots in California are subject to uniform rates—which charge the same amount for every gallon—or increasing block rates—which charge more per gallon for higher levels of use (Hanak, 2005). (Seasonal pricing, under which rates are increased during the summer months of peak demand, is rarely used in California.) Since 1991, the California Urban Water Conservation Council has encouraged the adoption of “conserva- tion pricing”—with rates set as close as possible to the utility’s own long-run marginal cost of water, using either uniform or increasing block rates.22 Although water is a relatively “inelastic” com- modity, recent evidence suggests that consumers are more sensitive to water prices than previously thought.23 It appears that price sensitivity is higher when customers face increasing block rates rather than uniform rates.24 Custom- ers also appear to be more sen- Although water is a relatively “inelastic” commodity, recent evidence suggests that sitive to prices for outdoor than indoor uses (Mansur and Olmstead, 2006). These findings suggest that increasing block rate structures may be better than consumers are more sensitive to water prices than previously thought. uniform rates at encouraging conservation—and that pricing can be an especially important outdoor conservation tool. (Flat rates, in contrast, offer no incen- tive to conserve.) Increasing block rate structures also have a built-in equity component, given that larger lots and higher water use within an area are generally associated with higher-income house- holds. To see how water rate structures interact with residential land use patterns, we matched our single-family lot data with water rate data for the four-fifths of our sample residing within the ser- vice areas of large utilities (Table 5).25 As the table makes clear, water rates are least conducive to conservation in some of the state’s hottest areas. However, flat and declining rate structures do not appear to be encouraging larger average lot sizes; lots are actually largest in the Central and Desert zone communities with increasing block rates.26 Increasing block rate structures are most prevalent in the Coastal and Inner Coastal zones, where water authorities have been more active in statewide conservation programs. Many utilities adopted these rate structures following the early 1990s drought. However, there has been little progress in shifting to increasing block rate structures or away from flat rate structures since the mid-1990s (Hanak, 2005). Recent efforts to put conservation pricing back on the front burner come from two quarters. One is the Landscape Task Force, which developed new conservation pricing guidelines to encourage utilities to send more accurate price signals to customers.27 The other is the California legislature, which has been pushing utilities with flat rates to convert to metering. After more than a decade of political wrangling, the legislature passed AB 2572 in 2004, which requires that all utilities with 3,000 or more customers install meters over the next two decades and begin using installed meters for billing by 2010. (Since 1992, builders have been required to install meters in new homes, but utilities have not been required to read them.) Some communities are starting to see the potential conservation benefits of this change: For instance, the fast-growing town of Lodi aims to finish installing meters long before the 2024 deadline, to realize conservation savings sooner (Hood, 2005). Smart Sprinklers Automatic sprinkling systems are popular because they are more convenient than manually operated hoses or sprinklers. The problem is that they often operate for too long or at times when watering is not needed. (As a rule of thumb, these systems operate with an irrigation efficiency rate of 50 percent or less.28) Rather than encourage people to go back to manual systems, many utilities are looking to address this problem by promoting “ET” or 12 P u b l ic P o l ic y I n stit u te of C a l ifor n ia California Economic Policy Lawns and Water Demand in California Table 5. Average Small Single-Family Lot Sizes by Water Rate Type Flat Declining Block Uniform Increasing Block ET0 Superzone Coastal Inner Coastal Average % of Average % of Average % of Average % of (square feet) Lots (square feet) Lots (square feet) Lots (square feet) Lots 7,617 0 16,711 0 7,202 43 7,327 57 n/a 0 10,913 0 8,905 44 9,351 56 Central Desert 8,306 9,429 49 2 8,266 n/a 6 8,051 29 10,083 16 0 10,929 62 11,709 37 Total 8,308 7 8,324 1 8,396 42 8,727 50 Source: Authors’ calculations, using county assessor records through 2002. Notes: Percentages show the share of homes in each climatic zone with each type of rate structure. Data include lots of one acre or less. “smart” irrigation controllers, which automatically adjust watering times based on plant cover and weather conditions. Smart controllers can operate either with on-site weather sensors or with communication links to a centralized weather-monitoring system.29 Previously limited to large commercial or public landscapes, smart controllers are now available to residential customers through rebate programs in several water districts. Field studies have shown that smart controllers can reduce residential water use considerably. In 2000, the Irvine Ranch Water District (IRWD) retrofitted 33 high-water-using homes with ET controllers.30 After two years, these homes had reduced their total water consumption by 41 gallons per household per day—approximately 18 percent of outdoor water use. In 2002, several water districts targeted high residential water users in Santa Barbara County. By 2003, 62 customers had switched to ET controllers, and preliminary results indicate that their average total water use has gone down by 26 percent.31 The Metropolitan Water District of Southern California (MWDSC), the large wholesale utility serving much of Southern California, estimates that smart controllers, in conjunction with highly efficient spray nozzles, could reduce outdoor residential water use by 28 percent within its service area.32 If ET controllers can save this much water, are they a good investment? To find out, we calculated the cost of saving water in different regions, using the savings rates obtained in field trials. Table 6 presents consumer and utility costs under some different scenarios. The calculations assume the use of a new, smart controller in a typical small lot in each of the four climatic zones, currently planted half turf and half shrubs and trees and being watered at 50 percent irrigation efficiency.33 The top panel of the table shows scenarios for water savings and customer costs. For the cost of the ET controller itself, the “low” alternative is for purchase and professional installation of an on-site sensor system and the “high” alternative is for a satellite system, which has a higher up-front cost and a monthly subscription fee.34 These costs are shown spread out over 15 years (the estimated life of the controller), both with and without utility rebates of $180 to $220 per system.35 The table’s bottom panel shows the water costs to utilities and the potential water bill savings for customers. Utility costs are expressed as the investment costs of procuring this “new” water through the rebate program, again on the assumption that the savings are available for only 15 years. We include an allowance for administrative costs.36 For consumers, the best bet is likely to be controllers with on-site sensors. With the utility subsidy, these systems generate enough savings on the water bill to more than cover the $9 in annualized costs, even with lower efficiency gains and in places with 13P u b l ic P o l ic y I n stit u te of C a l ifor n ia California Economic Policy Lawns and Water Demand in California Table 6. Smart Controller Costs and Savings ET Superzone Coastal Inner Coastal Central Desert Water Savings (gallons per day per household) Low (15%) High (25%) 22 37 36 60 38 63 60 101 Costs to Utility ($/acre-foot) Inputs Full cost After rebate Annual Cost to Customer (per controller) Low (on-site) High (satellite) $26 $95 $9 $79 Outputs Annual Savings to Customer (per controller) Low Water Price ($242/acre-foot) High Water Price ($678/acre-foot) ET Superzone Coastal Inner Coastal Central Desert Low Water Savings 584 397 379 256 High Water Savings 350 238 228 154 Low Water Savings 6 10 10 16 High Water Savings 17 27 29 46 Low Water Savings 10 16 17 27 High Water Savings 28 46 48 76 Notes: Assumes that 25 percent of water needs is met by rainfall. Both utility and customer investments are amortized at a rate of 4 percent. low water prices (the sole exception is low prices and low savings in the Coastal zone).37 Meanwhile, it is hard to break even with the satellite-linked systems, which cost $79 after rebate, mainly because it is harder to cover the on-going subscription costs (now $48 per year) through water bill savings. For utilities, the calculus involves comparing the costs of water procured through the rebate program with the costs of alternative sources. By this yardstick, these rebate programs have the potential to be cost effective. As a point of comparison, desalinated water has estimated annual costs in the range of $800 to $1,500 per acre foot, and average costs for recycled wastewater are estimated at $600 (Department of Water Resources, 2003a, 2003b).38 For both customers and utilities, savings would improve under rebate programs targeting high water users—those with particularly low irrigation efficiency, larger yards, and a higher share of turf in their overall yard mix. For customers, the sav- ings would also improve if ET controllers reduce other costs (e.g., less wastage of fertilizers and pesticides from overwatering).39 To the extent that ET controllers also help curb urban run-off, these programs can bring additional local benefits in pollution control.40 However, smart controllers do not address other sprinkler system problems, such as incorrectly set valves or sprinkler heads or other inefficiencies in the layout of the system. For this reason, consumer education needs to accompany these programs. Water-Wise Landscapes Water consumption can also be greatly reduced through the use of drought-tolerant plants. Throughout the American West, utilities have promoted “water-wise” landscaping since the mid-1990s. Outreach efforts have focused not only on educating people about the water savings potential but also on the attractiveness of these landscapes, which 14 P u b l ic P o l ic y I n stit u te of C a l ifor n ia California Economic Policy Lawns and Water Demand in California include many beautiful, flowering plants, not just prickly cacti and rocks. Because plant availability can be a problem, utilities have begun locating their demonstration gardens at home and garden stores. The hope is that this will encourage major retailers like Home Depot to stock native plants, which they have begun doing only recently. Consumer education can be a major undertaking. Since 2002, MWDSC has spent more than $6 million on advertisements to promote “California friendly” landscaping, designed to reduce overwatering and encourage the use of native plants.41 To add teeth to these efforts, some water districts have launched turf buy-back programs, or socalled “cash-for-grass” initiatives. Through these programs, utilities pay customers to replace turf with less water-intensive plants and to install drip irrigation. Rebates range from $0.40 per square foot in Victorville, California, to $1 per square foot in Las Vegas, Nevada. These rebates cover only a portion of the cost to the consumer to replace turf. The Southern Nevada Water Authority (SNWA), which runs the Las Vegas program, estimates that customers pay from $2 to $5 per square foot to convert their landscapes.42 The potential water savings come from the combined effect of lower plant needs and higher irrigation efficiency, and they are truly spectacular. Well-installed drip irrigation can attain efficiency levels approaching 90 to 95 percent, and low-water plants need only 20 percent of the ET0 rate (compared to 80 percent for lawns). A conversion of a cool-season turf lawn using a “dumb” automatic sprinkler system to a “smart” drip-irrigated garden with drought-tolerant plants could move overall plant needs from 160 percent to as low as 21 percent (Table 4). Although the savings in practice are more modest, they are nevertheless considerable. Drawing on detailed field surveys, SNWA estimates that conversion from turf to low-water landscaping brought water use down from 73.0 gallons of water per square foot to just 17.2 gallons per square foot, a 76 percent savings.43 The agency has encouraged residential customers to go for varied landscapes, keeping turf grass in places where they actually use it. Between 2001 In Las Vegas, conversion and 2005, SNWA bought back over 1,500 acres of turf, or over 11,300 acre-feet of water. Purchases went up dramatically in 2003, when the rebate was raised from turf to low-water landscaping brought water use down from 73.0 gallons of water per from $0.40 to $1.00 per square square foot to just 17.2 foot. How might such a program fare in California? Table 7 com- gallons per square foot, a 76 percent savings. pares the costs to utilities and customers of turf buy-back programs across Cali- fornia’s climate zones, assuming water savings sim- ilar to that in Las Vegas (76%). To calculate these savings, we assume lower irrigation efficiency than in the smart controller example above (37.5% ver- sus 50%).44 Water savings and costs are shown per square foot, so that the only variation across zones is due to climate. Utility costs assume 15 years of savings, as above. For customers, costs are shown in terms of the number of years needed to recoup the net investment, assuming a total conversion cost ranging between $2 and $2.60 per square foot. The three payback scenarios reflect different assumptions about the savings from conversions: (1) savings on the water bill only, (2) additional savings from lower expenditures on garden sup- plies, and (3) additional savings from lower labor expenditures on garden maintenance. These “non- water” savings are drawn from a survey in the Las Vegas area, which found that homes with a greater proportion of lawns had higher labor and supply costs for mowing and other aspects of lawn main- tenance.45 It must be stressed that these results may not be representative. For consumers, the water savings alone are un- likely to be a significant draw, even with a generous utility rebate. The picture changes dramatically, however, if homeowners reap additional savings in terms of lower garden supply and labor costs. These savings even make conversion a potentially attrac- tive proposition in coastal areas and with higher net costs. These very different results underscore the importance of improving our understanding of 15P u b l ic P o l ic y I n stit u te of C a l ifor n ia California Economic Policy Lawns and Water Demand in California Table 7. Turf Conversion Costs and Savings Customer Years to Recoup Investment Low Net Conversion Costs ($1.00/square foot) ET0 Superzone Coastal Inner Coastal Water Savings (gallons/square foot) 32 39 I II III 23 6 3 17 6 2 Central Desert 42 51 15 5 2 12 5 2 Costs to Utility ($/acre-foot) High Net Conversion Costs ($1.60/square foot) Low Rebate ($0.40/square foot) High Rebate ($1.00/square foot) I II III Coastal 363 907 76 10 4 Inner Coastal 298 745 38 10 4 Central 276 690 32 9 4 Desert 232 580 23 8 4 Notes: Assumes a retail water price of $678 per acre-foot. Scenario I includes only water savings, scenario II also includes garden supply savings, and scenario III includes labor cost savings. Both utility and customer investments are amortized at a rate of 4 percent. Baseline irrigation efficiency is 37.5 percent, with 25 percent of plant water needs met by rainfall (or alternatively, 50% irrigation efficiency with no rainfall contribution). the total costs of landscape alternatives to households, not just the water savings. For utilities, purchasing water through a cash-for-grass program appears to be a considerably more expensive proposition than the rebate program for smart controllers, particularly at the price of $1 per square foot and in the milder climate zones. Actual costs may be higher, as we have not included the costs of program administration and we have assumed very high rates of water savings. If, on the other hand, the program creates a permanent shift in landscaping habits, rather than the 15 years assumed here, this would lower costs by about a third. As with smart controllers, there are additional benefits in control of polluted run-off. Regulating Landscapes In addition to public education and rebate programs, which aim to change tastes and behavior through voluntary means, some localities are emphasizing regulations. Such policies typically take the form of local ordinances, and they target landscaping practices in public, commercial, and residential areas. In California, the initial push for landscape regulations came from the state legislature, during the early 1990s drought. In 1990, the Water Conservation in Landscaping Act (AB 325) required that DWR draft a model waterefficient landscape ordinance. The model ordinance contained a number of stipulations involving irrigation design and efficiency and the use of native plants.46 It applied to large commercial and public landscapes and to residential landscapes installed by developers. Local agencies were required to adopt the model ordinance, adopt their own ordinance, or issue legal findings that they did not need an ordinance. Although most cities and counties complied with the statute, actual implementation of the local ordinances has been inconsistent, and program monitoring has been minimal (Bamezai, Perry, and Pryor, 2001). 16 P u b l ic P o l ic y I n stit u te of C a l ifor n ia California Economic Policy Lawns and Water Demand in California Some of the most enthusiastic local adopters are in fast-growing inland areas of Southern California. Many towns now require that developers use “California friendly” plants in all road medians and other public spaces. The City of Lancaster, for example, located in a hot area of eastern Los Angeles County, requires that all public landscaping be drought-tolerant. Several desert cities and utilities have adopted more widely applicable landscape ordinances. The Coachella Valley Water District (2003) recently adopted an ordinance requiring that new and refurbished landscaping feature vegetation that uses 25 percent less water than that required by the model ordinance. Other localities are taking the lead from cities in neighboring southwestern states, where landscaping restrictions have become increasingly common. In weighing the pros and cons of landscape regulation, it is important to consider the value of lawns to households and communities. To the extent that lawns provide recreational space, lowwater plants, no matter how beautiful, are not a good substitute. Even though common area lawns may be a more efficient way to provide this space, many households may prefer to have their own lawns for privacy and safety reasons. These considerations suggest that cost savings alone will not be enough to motivate all residents to make the switch. Encouraging people to cut back on turf in places where they do not use it—such as front yards and median strips—may be a more effective strategy than encouraging wholesale lawn removal.47 What Role for State Policy? Many outdoor conservation policies stem from local and regional initiatives, but the state has not been absent from the scene. Various rebate programs are supported by state grants, state legislation provided the impetus for landscape ordinances, and legislation now requires that utilities start using meters to bill for water use. The recommendations of the Landscape Task Force, presented to the governor and the legislature in December 2005, call for the state to play a greater role in the future. The report contains 43 recommendations covering a wide range of actions (California Urban Water Conservation Council, 2005). In addition to stressing the importance of rate structure reform and more education and training, the recommen- dations focus on regulatory approaches: requiring smart irrigation controllers and dedicated land- scape meters, adopting and enforcing statewide prohibitions on overspray and runoff, and strengthening and enforcing compliance with landscape ordinances. They also call for improvements in the knowledge base on irrigation requirements and plant water needs in Outdoor water conservation will need to be an important policy focus in many parts of the state, different parts of the state. This both to limit increases includes extending the California Irrigation Management Information System (CIMIS)—a network of weather stations designed to gauge irrigation needs—to more in water demand and to free up water supplies to accommodate new residents. urban areas. The emphasis on regulation parallels the estab- lished approach to indoor conservation; state and federal regulations on plumbing fixtures and appli- ances are widely viewed as central to the successes achieved to date. For the outdoor environment, where there is considerably more variability in the potential for water savings, it will be especially im- portant to weigh the costs and benefits to house- holds and to society before imposing regulatory solutions. As with indoor appliances, regulations focusing on new construction may have the great- est potential to achieve a beneficial outcome. Conclusion The magnitude and geographical distribution of population growth in California are poised to exert significant pressure on the state’s water delivery systems over the coming decades. Outdoor water conservation will need to be an important policy focus in many parts of the state, both to limit increases in water demand and to free up water supplies to accommodate new 17P u b l ic P o l ic y I n stit u te of C a l ifor n ia California Economic Policy Lawns and Water Demand in California residents. Key elements of the policy toolkit include water rate reform; the use of new, “smart” watering methods; and landscaping changes that reduce water use. Many utilities are focusing on education and outreach to provide households with information on alternatives and to make low-water plants more readily available at nurseries. Some are proposing rebates. Regulatory restrictions on landscaping of new homes—restricting lawns to a fraction of the yard—are still rare in California but increasingly common in neighboring states. Our analysis suggests that rebates to homeowners may be a costeffective way to improve irrigation systems, particularly in the hotter, dryer regions and when water prices are higher. The savings from replacing turf with low-water plants are less obvious. For new homes, it may be easier (and more cost-effective) to build “water smart” from the ground up. Whether education and outreach (particularly with builders) is sufficient to encourage this goal, or whether regulatory solutions are required, is still an open question. Conservation-oriented water rates, which signal water scarcity to households, should be a part of any conservation package. v Notes 1 An analysis of 2000 Census housing data by tract reveals that the average “reference evapotranspiration rate”—a measure of plant water needs resulting from climate— increased significantly in both the San Francisco Bay Area and the South Coast region for housing built since 1980. See the discussion on evapotranspiration zones. For trends in individual counties, see the web-only data box, http://www. ppic.org/content/other/706EHEP_web_only_appendix.pdf. 2 For a sample of 1,129 households with sprinklers, Maddaus and Mayer (2001) found that the addition of an automatic sprinkler increased outdoor use by 55 to 60 percent. In the hotter zones, 57 percent of surveyed homes used these systems compared to 20 percent in the cooler, wetter climates. 3 An acre-foot of water is equivalent to 325,851 gallons, the amount of water it takes to cover an acre of land one foot deep. One acre-foot is the amount of water used annually by five to eight people. 4 The Plan cites several studies suggesting the potential for significant, cost-effective savings. A Pacific Institute study (Gleick et al., 2003) estimated that urban water use could be reduced by roughly 12 percent at a cost of $100 per acre-foot or less and by as much as a third at less than $600 per acre-foot (the benchmark price used by the study authors for alternative sources). The California Urban Water Agencies (2001, 2004) estimate that implementation of quantifiable “best management practices” (a narrower set of goals) would generate just over one million acre-feet cost-effectively by 2030. A study for the California Bay Delta Authority (2005) estimates a savings potential of up to 3.1 million acre-feet, although the last million might not be cost-effective. 5 Measurement of water use in the “large landscape” category is more precise, thanks to separate meters. 6 See http://www.snwa.com/html/cons_waterfacts.html. 7 Although the graph only shows trends back to 1945, the cumulative average extends back to the earliest records, as early as 1803 in the South Coast. 8 Single-family home sizes in California grew from an average of 1,277 square feet in the mid 1940s to nearly 2,600 square feet by the early 2000s. Building footprints increased from roughly 1,200 square feet to 1,900 square feet over this interval. It is possible that the total amount of hardscape—including garage area and pavement, in addition to the home’s footprint—has increased by a greater amount, but we have no way to measure this. 9 Because the data on lot sizes are less precise for some of these counties, it is possible that our analysis overstates the importance of these lots in the overall picture. Also, some of these ranchettes may be hobby farms or vineyards, for which water use would fall within agricultural demand. 18 P u b l ic P o l ic y I n stit u te of C a l ifor n ia California Economic Policy Lawns and Water Demand in California 10 The Coastal superzone includes ET0 zones 1 through 5, the Inner Coastal superzone includes ET0 zones 6 through 10, the Central superzone includes ET0 zones 11 through 15, and the Desert superzone includes ET0 zones 16 through 18. 11 This percentage is in line with recent field studies by the East Bay Municipal Utility District (EBMUD). In a 1995 survey, an average of 2,513 square feet, or 26 percent of the total lot, was irrigated—corresponding to roughly 31 percent of our definition of yard (Opitz and Hauer, 1995). In a 2001 survey, average irrigated area was estimated as roughly the same (2,510 square feet), but no total lot size was given (Water Resources Engineering, Inc., 2002). Our estimates from county assessor records suggest that this corresponds to roughly 36 percent of total lot size. 12 The weighted average ET0 for each region and superzone is calculated based on the number of lots in each of the 18 detailed ET zones. The numbers shown here reflect regional and zonal ET0 using the distribution of single-family homes in the county assessor records. The results are nearly identical when we use the rates calculated from the distribution of homes in the 2000 Census. 13 We also evaluated higher percentages, but these implied far too much aggregate outdoor residential water demand relative to DWR’s estimates of total residential use. 14 This estimate is derived using the 2000 Census estimate of the share of multifamily units in the total (32.9%) and DWR’s estimate that multifamily units accounted for 26.8 percent of residential water use in that year (see Department of Water Resources, 2004). For that same year, DWR (2005) estimates average indoor residential use at 3,233,000 acre-feet, or 0.28 acre-feet per household, and average outdoor use at 2,328,000 acre-feet. If average multifamily and single-family indoor use is the same, this implies an average single-family outdoor use of 0.24 acrefeet and average multifamily outdoor use of 0.11 acre-feet, 46 percent of the single-family value. We apply a rate of 50 percent, because it is also likely that multifamily homes have somewhat lower indoor use. Note that these ratios are similar to those found by Dzieglielewski et al. (1990) in a study conducted in Southern California (Department of Water Resources, 1994a). 15 The estimates are obtained by multiplying the average lot sizes in each ET0 superzone by the volume of single and multifamily housing reported in the 2000 Census. 16 The additional effect of shifts in the average ET0 rate was a 7 percent increase in the Bay Area and a 3 percent increase in the South Coast. In the inland regions, the increases are under 1 percent. 17 A recent survey of single-family homes in the EBMUD service area found, for instance, that roughly a quarter of all households had no irrigated landscape in the front or back yard (Water Resources Engineering, Inc., 2002). 18 This is the standard for cool-season turf grass embodied in California’s Model Landscape Ordinance, for instance. 19 In the EBMUD studies, lawns accounted for about 40 percent of the irrigated landscape (Opitz and Hauer, 1995; Water Resources Engineering, Inc., 2002). The Metropolitan Water District of Southern California’s outdoor water conservation programs assume that a conventional landscape consists of 60 percent lawn and 40 percent shrubs and trees. 20 We obtained these figures by comparing outdoor water use estimates in the inland and coastal areas with our estimates of irrigated acreage and assuming that 25 percent of plant water needs are covered by rainfall. With DWR’s estimate of outdoor residential water use (2.3 million acrefeet, or 42 percent of all residential use), we obtain an ET factor of 106. If outdoor use instead made up half of the residential total, the ET factor jumps to 127. Rates are higher in the inland regions in both scenarios. 21 Hayhoe et al. (2004); Lund et al. (2003); Department of Water Resources (2005). 22 The long-run marginal cost is the incremental per unit cost of expanding water supply, taking into account both investment and operational costs. 23 In part, this new view stems from improved estimation techniques, which better capture the effect of fixed fees and jumps in prices associated with increasing block rates. See Hanemann and Hewitt (1995). 24 In a study based on a climatically and geographically diverse dataset, Olmstead, Hanemann, and Stavins (2005) find that households subject to increasing block rate water prices exhibit nearly double the price elasticity of houses subject to uniform pricing structures. The study found a price elasticity of –0.64 for increasing block rate households versus –0.33 for uniform pricing households. In a meta-analysis incorporating over 300 estimates of water price elasticity, Dalhuisen et al. (2003) also found greater price sensitivity under increasing block rate systems. 25 The data on rate structures are from Black and Veatch (2001, 2003) and phone surveys. The sample included 348 utilities meeting the size threshold for the Urban Water Management Plans Act (at least 3,000 customers or 3,000 acre-feet of annual water sales). 26 In particular, this group includes water districts in the Sacramento Metro region, the Inland Empire, and Los Angeles County. Most switched from uniform to increasing block rates in the early to mid-1990s. 27 In practice, this is proposed through benchmark shares of volumetric pricing in total revenues. To qualify as conservation pricing, 60 percent of total revenue through a tiered rate structure must come from volumetric revenue (as opposed to revenue from fixed charges). For uniform rate structures, volumetric revenue must constitute at least 75 of total revenue. See California Urban Water Conservation Council (2005). 28 This is the rate the Metropolitan Water District of Southern California is assuming in its estimates of potential water savings from improved irrigation efficiency, for 19P u b l ic P o l ic y I n stit u te of C a l ifor n ia California Economic Policy Lawns and Water Demand in California instance. Maddaus and Mayer (2001) estimate that these rates could be even lower, within the range of 30 to 50 percent. 29 On-site systems rely on either a solar sensor or a temperature sensor, in both cases combined with a rain sensor. 30 Bamezai (2001); Hunt, et al. (2001); Municipal Water District of Orange County and Irvine Ranch Water District (2004). IRWD did not adjust the controllers after installation to simulate the minimal consumer adjustment that they expected would happen under normal circumstances. 31 Santa Barbara County Water Agency (2003). 32 Interview with Lynn Lipinski, John Wiedman, and Tim Blair, MWDSC, October 28, 2005; Kissinger and Solomon (2005). With these technologies, irrigation efficiency would jump from 50 to 69 percent. 33 For a typical home in the Coastal zone, our estimates generate slightly lower per household savings from ET controllers than the 41 gallons per day found in the Irvine Ranch Water District (Bamezai, 2001). That pilot study targeted water users in the top 20 percent of households, who likely had either larger lawns, lower irrigation efficiency, or a combination of these factors. 34 See http://www.mwdoc.com/SmarTimer/ETControllers. htm for a list of products eligible for rebates under a joint program by the Municipal Water District of Orange County and the Irvine Ranch Water District. One system listed has a starting price of $1,400, but it is mainly directed at commercial clients. The price of on-site sensor-based controllers ranges from $140 to $260 for an eight-valve system, and the price of satellite-linked systems starts in the range $560 to $650. After year two, a monthly subscription fee of $4 is charged. Installation costs range from $75 to $130 (the higher price includes rooftop installation of solar sensors). 35 Utility rebates are assumed to be $20 per valve. For the Coastal zone, we assume an average of nine valves (the current practice in Orange County); for the Inner Coastal and Central zones, an average of ten valves; and for the Desert zone, an average of 11 valves, to take into account larger lot sizes. 36 We assume a cost per controller of $40, in line with current programs in Orange County. 37 These rates are calculated for a sample of 251 utilities with uniform rates using data in Black and Veatch (2003). The “low” price ($242/acre-foot) is the average rate charged in 2003 in the San Joaquin Valley, and the “high” price ($678/acre-foot) is the comparable rate for the South Coast region. Average rates were higher in the Bay Area ($827) and the Central Coast ($711) and lower in the Inland Empire ($453) and the Sacramento Valley ($265). Marginal rates may be higher in some increasing block rate systems, which are not included in these calculations. 38 Some urban utilities have access to lower-cost sources, notably through purchases of farm water and underground storage, which can cost as little as $100 to $200 per acrefoot in some locations (Hanak, 2005). 39 For instance, Gleick et al. (2003) have argued that the non-water cost savings from more efficient irrigation practices could be substantial. 40 The Irvine studies mentioned above found that run-off was reduced by 50 percent for homes retrofitted with ET controllers (Municipal Water District of Orange County and Irvine Ranch Water District, 2004). 41 Interview with Lynn Lipinski, John Wiedmann, and Tim Blair (MWDSC), October 28, 2005. 42 Information provided by Tracy Bower, SNWA, February 2005 and Kent Sovocool, SNWA, January 2006. These estimates cover turf removal and installation of the new landscape, including a drip irrigation system. During the SNWA’s field study in the late 1990s (Sovocool, 2005), the average costs were on the order of $2 per square foot. These costs have been rising in recent years, in part because more people are using contractors to do the conversion and in part because of a loss of scale economies as people convert smaller plots. 43 Using irrigation submeters, SNWA monitored over 300 single-family homes that had converted at least 500 square feet of turf grass to “xeric” (low-water) landscapes (Sovocool, 2005). 44 This assumes, as above, that 25 percent of water needs are met by rainfall. Alternatively, the same ET adjustment factor (160%) could be attained with 50 percent irrigation efficiency and no allocation of rainfall to cover plant needs. 45 The maintenance survey was conducted by mail in the summer of 2000, drawing from a sample of participants in SNWA’s turf conversion program. Respondents were asked to record their time and capital costs (lawnmowers, fertilizers, etc.) for their residential landscapes. Usable records on costs were available for 216 cases, of which 50 had at least 60 percent turf in their gardens and 166 had at least 60 percent xeriscape landscape, with an average landscaped area of 1,750 square feet. The annual capital costs were $214 lower for the yards with more xeriscape (yielding a savings of $0.12/square foot), and these residences used 2.3 fewer hours of labor per month (yielding a savings of $0.23/square foot if valued at $14.50 per hour, a price assumed for unskilled landscaping work). See Hessling (2001) and Sovocool (2005). 46 Notably, it set a standard for irrigation efficiency of at least 62.5 percent, and it advocated a 1/3:1/3:1/3 crop mix (see Table 4). For details, see California Urban Water Conservation Council (2005). 47 For an overview of flexible, water-smart landscaping approaches, see Department of Water Resources (2002). 20 P u b l ic P o l ic y I n stit u te of C a l ifor n ia California Economic Policy Lawns and Water Demand in California References Bamezai, Anil, “ET Controller Savings Through the Second Post-Retrofit Year: A Brief Update,” Western Policy Research, April 2001, available at http://irwd.com/Conservation/ETsavings1.pdf. Bamezai, Anil, LADWP Weather-Based Irrigation Controller Pilot Study, Western Policy Research, August 2004, available at http://www.cuwcc.org/uploads/product/LADWP-IrrigationController-Pilot-Study.pdf. Bamezai, Anil, Robert Perry, and Carrie Pryor, Water Efficient Landscape Ordinance (AB 325): A Statewide Implementation Review, a report submitted to the California Urban Water Agencies, Western Policy Research, Santa Monica, California, March 2001. Baumann, Duane D., John J. Boland, and W. Michael Hanemann, Urban Water Demand Management and Planning, McGraw-Hill, New York, 1997. Black and Veatch, California Water Charge Survey, Management Consulting Division, Irvine, California, 2001. Black and Veatch, California Water Charge Survey, Management Consulting Division, Irvine, California, 2003. Bowles, Jennifer, “Inland Area’s Thirst Growing,” The Press-Enterprise, Riverside, California, July 27, 2005. California Bay Delta Authority, “Final Draft Year 4 Comprehensive Evaluation of the CALFED Water Use Efficiency Element,” Sacramento, California, December 2005. California Urban Water Agencies, Urban Water Conservation Potential, Sacramento, California, August 2001. California Urban Water Agencies, Urban Water Conservation Potential 2003 Technical Update, Sacramento, California, July 2004. California Urban Water Conservation Council (CUWCC), Water Smart Landscapes for California. AB 2717 Landscape Task Force Findings, Recommendations and Actions, report to the Governor and the Legislature, Sacramento, California, December 2005. Coachella Valley Water District, “CVWD Board Approves Water-Efficient Landscape Model Ordinance,” CVWD Press Release, March 2003, available at http://www.cvwd. org/pressrel/Landscape_Ordinance.pdf. Dalhuisen, Jasper M., Raymond J.G.M. Florax, Henri L.F. de Groot, and Peter Nijkamp, “Price and Income Elasticities of Residential Water Demand: A MetaAnalysis,” Land Economics, Vol. 79, No. 2, May 2003, pp. 292–308. Department of Finance, Population Projections by Race/ Ethnicity, Gender and Age for California and Its Counties 2000–2050, Sacramento, California, May 2004. Department of Finance, E-1 City/County Population Estimates, with Annual Percent Change, January 1, 2004 and 2005, Sacramento, California, May 2005. Department of Water Resources, Implementation of the California Water Plan, Bulletin 160-66, Sacramento, California, 1966. Department of Water Resources, Water for California: The California Water Plan, Outlook in 1970, Bulletin 160-70, Sacramento, California, 1970. Department of Water Resources, California Water Plan, Bulletin 160-74, Sacramento, California, 1974. Department of Water Resources, The California Water Plan: Projected Use and Available Water Supplies to 2010, Bulletin 160-83, Sacramento, California, 1983. Department of Water Resources, Memorandum Report Additional Information for Bulletin 160-87, Sacramento, California, 1987. Department of Water Resources, Urban Water Use in California, Bulletin 166-4, Sacramento, California, August 1994a. Department of Water Resources, California Water Plan Update, Bulletin 160-93, Sacramento, California, 1994b. Department of Water Resources, California Water Plan Update, Bulletin 160-98, Sacramento, California, November 1998. Department of Water Resources, Water-Efficient Landscapes, Office of Water Use Efficiency, 2002, available at http://www.owue.water.ca.gov/docs/water_efficient_landscapes.pdf. Department of Water Resources, Water Recycling 2030: Recommendations of California’s Recycled Water Task Force, Sacramento, California, June 2003a. Department of Water Resources, Water Desalination: Findings and Recommendations, Sacramento, California, October 2003b. Department of Water Resources, Water Use–Water Supply Balances, California Land and Water Use, Sacramento, California, April 2004, available at http://www.landwateruse. water.ca.gov. Department of Water Resources, California Water Plan Update, Bulletin 160-05, Sacramento, California, December 2005. Dzieglielewski, B., et al., Seasonal Components of Urban Water Use in Southern California, Planning and Management Consultants, Ltd., Carbondale, Illinois, 1990. Gleick, Peter H., Dana Haasz, Christine Henges-Jeck, Veena Srinivasan, Gary Wolf, Katherine Kao Cushing, 21P u b l ic P o l ic y I n stit u te of C a l ifor n ia California Economic Policy Lawns and Water Demand in California and Amardip Mann, Waste Not, Want Not: The Potential for Urban Water Conservation in California, The Pacific Institute, Oakland, California, November 2003. Hanak, Ellen, Who Should Be Allowed to Sell Water in California? Third-Party Issues and the Water Market, Public Policy Institute of California, San Francisco, California, 2003. Hanak, Ellen, Water for Growth: California’s New Frontier, Public Policy Institute of California, San Francisco, California, 2005. Hanemann, W. Michael, and Julie A. Hewitt, “A Discrete/ Continuous Choice Approach to Residential Water Demand under Block Rate Pricing,” Land Economics, Vol. 71, 1995, pp. 173–192. Hayhoe, Katharine, et al., “Emissions Pathways, Climate Change, and Impacts on California,” Proceedings of the National Academy of Sciences, Vol. 101, No. 34, August 2004, pp. 12422–12427. Hessling, Michael, “Turf Landscapes versus Xeriscapes: Analysis of Residential Landscapes in the Las Vegas Valley, Nevada,” master’s project submitted in partial fulfillment of the requirements for the Master of Environmental Management degree in the Nicholas School of the Environment of Duke University, Durham, North Carolina, 2001. Hood, Jeff, “Lodi Council Wants Water Meters in Sooner,” Stockton Record, December 7, 2005. Hunt, Theodore, Dale Lessick, et al., “Residential WeatherBased Irrigation Scheduling: Evidence from the Irvine ‘ET Controller’ Study,” Irvine Ranch Water District, June 2001, available at http://www.irwd.com/welcome/FinalETRpt.pdf. Kissinger, Joseph, and Kenneth H. Solomon, “Uniformity and Water Conservation Potential of Multi-Stream, MultiTrajectory Rotating Sprinklers for Landscape Irrigation,” June 2005, available at http://www.cuwcc.org/landscape_ task_force/SolomonKissinger.pdf. Lund, Jay, et al., Climate Warming and California’s Water Future, Report 03-1, Center for Environmental and Water Resource Engineering, University of California, Davis, California, March 2003. Maddaus, Lisa, and Peter W. Mayer, “Splash or Sprinkle? Comparing the Water Use of Swimming Pools and Irrigated Landscapes,” paper presented at the annual conference of the American Water Works Association, Washington, D.C., 2001. Mansur, Erin T., and Sheila M. Olmstead, “The Value of Scarce Water: Measuring the Inefficiency of Municipal Regulations,” AEI-Brookings Joint Center for Regulatory Studies, Working Paper 06-01, Washington, D.C., January 2006. Mayer, Peter W., William B. DeOreo, Eva M. Opitz, Jack C. Kiefer, William Y. Davis, Benedykt Dziegielewski, and John Olaf Nelson, Residential End Uses of Water, AWWA Research Foundation and American Water Works Association, Denver, Colorado, 1999. Municipal Water District of Orange County and Irvine Ranch Water District, The Residential Runoff Reduction Study, July 2004, available at http://www.irwd.com/Conservation/R3-Study-Revised11-5-04.pdf. Olmstead, Sheila M., W. Michael Hanemann, and Robert N. Stavins, “Do Consumers React to the Shape of Supply? Water Demand under Heterogeneous Price Structures,” Resources for the Future Discussion Paper 05-29, Washington, D.C., June 2005. Opitz, E. M., and R. J. Hauer (Planning and Management Consultants, Ltd), Water Conservation Baseline Study, prepared for the East Bay Municipal Utility District, Oakland, California, 1995. Santa Barbara County Water Agency, County ET Controller Distribution and Installation Program, Final Report, 2003, available at http://www.hydropoint.com/images/ pdf/SantaBarbaraYear1Report.pdf. Sovocool, Kent A., Xeriscape Conversion Study, Final Report, Southern Nevada Water Authority, 2005, available at http://www.snwa.com/assets/pdf/xeri_study_final.pdf. Water Resources Engineering, Inc., East Bay Municipal Utility District Water Conservation Market Penetration Study, final report, San Francisco, California, March 2002. 22 P u b l ic P o l ic y I n stit u te of C a l ifor n ia California Economic Policy Lawns and Water Demand in California About the Authors Ellen Hanak is a research fellow at the Public Policy Institute of California. Matthew Davis recently completed the Master of City Planning program at UC Berkeley. During the course of our research on outdoor water conservation policies, we received helpful input from numerous individuals working in water utilities and experts in water conservation technologies. We also thank Scott Matyac and Morrie Orang of the Department of Water Resources for initial guidance on the research and for making available information on evapotranspiration zones. David Haskel and Steve Ciccarella provided valuable research assistance. Dan Carney (Marin Municipal Water District), Michael Hazinski (East Bay Municipal Utilities District), John Landis (UC Berkeley), Jeff Loux (UC Davis), Scott Matyac, Marsha Prillwitz (California Urban Water Conservation Council), and Public Policy Institute of California colleagues Jon Haveman, David Neumark, and Michael Teitz provided helpful comments on a draft version of the report and Lynette Ubois and Patricia Bedrosian (RAND Corporation) provided valuable editorial assistance. Responsibility for any errors lies solely with the authors. Board of Directors Thomas C. Sutton, Chair Chairman and Chief Executive Officer Pacific Life Insurance Company Linda Griego President and Chief Executive Officer Griego Enterprises, Inc. Edward K. Hamilton Chairman Hamilton, Rabinovitz & Alschuler, Inc. Gary K. Hart Founder Institute for Education Reform California State University, Sacramento Walter B. Hewlett Director Center for Computer Assisted Research in the Humanities David W. Lyon President and Chief Executive Officer Public Policy Institute of California Cheryl White Mason Vice-President Litigation Legal Department Hospital Corporation of America Ki Suh Park Design and Managing Partner Gruen Associates Constance L. Rice Co-Director The Advancement Project Raymond L. Watson Vice Chairman of the Board Emeritus The Irvine Company Carol Whiteside President Great Valley Center The Public Policy Institute of California is a private, nonprofit research organization established in 1994 with an endowment from William R. Hewlett. The Institute conducts independent, objective, nonpartisan research on the economic, social, and political issues affecting Californians. The Institute’s goal is to raise public awareness of these issues and give elected representatives and other public officials in California a more informed basis for developing policies and programs. PPIC does not take or support positions on any ballot measure or on any local, state, or federal legislation, nor does it endorse, support, or oppose any political parties or candidates for public office. PUBLIC POLICY INSTITUTE OF CALIFORNIA 500 Washington Street, Suite 800 San Francisco, California 94111 Telephone: (415) 291-4400 Fax: (415) 291-4401 www.ppic.org ISSN #1553-8737 Recent issues of California Economic Policy Trade with Mexico and California Jobs Are Businesses Fleeing the State? Interstate Business Relocation and Employment Change in California A Decade of Living Wages: What Have We Learned? Recent Trends in Exports of California’s Information Technology Products The Workers’ Compensation Crisis in California: A Primer are available free of charge on PPIC’s website www.ppic.org Public Policy Institute of California 500 Washington Street, Suite 800 San Francisco, California 94111 In This Issue of CEP Lawns and Water Demand in California NON-PROFIT ORG. U.S. POSTAGE PAID Brisbane, CA PERMIT #83" } ["___content":protected]=> string(106) "

EP 706EHEP

" ["_permalink":protected]=> string(81) "https://www.ppic.org/publication/lawns-and-water-demand-in-california/ep_706ehep/" ["_next":protected]=> array(0) { } ["_prev":protected]=> array(0) { } ["_css_class":protected]=> NULL ["id"]=> int(8548) ["ID"]=> int(8548) ["post_author"]=> string(1) "1" ["post_content"]=> string(0) "" ["post_date"]=> string(19) "2017-05-20 02:38:34" ["post_excerpt"]=> string(0) "" ["post_parent"]=> int(3766) ["post_status"]=> string(7) "inherit" ["post_title"]=> string(10) "EP 706EHEP" ["post_type"]=> string(10) "attachment" ["slug"]=> string(10) "ep_706ehep" ["__type":protected]=> NULL ["_wp_attached_file"]=> string(14) "EP_706EHEP.pdf" ["wpmf_size"]=> string(7) "1168585" ["wpmf_filetype"]=> string(3) "pdf" ["wpmf_order"]=> string(1) "0" ["searchwp_content"]=> string(85678) "Public Policy Institute of California CEP California Economic Policy Ellen Hanak and David Neumark, editors Volume 2, Number 2 n July 2006 Lawns and Water Demand in California By Ellen Hanak and Matthew Davis California Economic Policy is a quarterly series analyzing and discussing policy issues affecting the California economy. SUMMARY O ver the next 25 years, California’s population is expected to grow by some 11 million residents, with over half of this growth occurring in the hotter inland counties. This shift raises the prospect of substantial increases in urban water demand, especially for outdoor uses, because landscaping typically accounts for at least half of all residential water use in inland areas. Because water demand growth poses both financial and environmental challenges, many water utilities are now launching conservation programs to curb water use outdoors. In this issue of CEP, we examine the role of residential land use in the demand for water outdoors, with a focus on the water needs of cool-season turf grass lawns. We also explore the savings potential of some key water conservation tools. Drawing on detailed residential housing data, we find that outdoor water needs for typical residential lots are likely to be more than two to three times higher in inland areas than along the coast. Although climate plays a role in this difference, residential land use patterns are far more important. Single-family homes, which typically use about twice as much landscaping water as multifamily units, make up a much larger share of inland housing. Inland areas also generally have larger lots, including a higher proportion of “ranchettes” (i.e., lots between one and 20 acres). Recent housing trends suggest some attenuation of these differences, with the rise of denser single-family tract developments in the Central Valley and the Inland Empire. But in contrast to the coast, where there has been a surge in multifamily housing since 2000, the inland region has seen multifamily homes continue to fall as a share of total housing. Recent conservation efforts have aimed to lower outdoor water use by improving the effi- ciency of landscape irrigation and replacing some lawns with less thirsty plants. Field studies suggest that both strategies offer considerable potential for saving water. At the state level, there has also been renewed attention to the role of water rates, which often fail to provide residents with correct signals about the scarcity of water resources. Conservation-oriented water rates can play an important role in both new and existing neighborhoods. Our analysis also suggests that improved irrigation technologies may be cost effective in many parts of the state, even when water rates are relatively low. By contrast, “cash for grass” programs, which give homeowners rebates for replacing turf with drought-tolerant plants, are likely to pay off only if the new landscapes also California Economic Policy Lawns and Water Demand in California lead to substantial savings in garden supplies and labor. Promotional strategies to implement conservation include public education and outreach, customer rebates, and regulatory restrictions on landscaping options. Whether education and outreach will be sufficient to encourage new development to be “water smart,” or whether regulatory solutions are required, is still an open question. Introduction Without efforts to reduce per capita water use, California faces significant increases in urban water demand over the coming decades—a prospect that poses both environmental and financial challenges. Lawns are one of the biggest culprits. Outdoor water use often accounts for half or more of all residential water demand, especially in the hotter inland areas where population growth is now fastest. California’s inland counties are expected to accommodate over half of the 11.3 million new California residents anticipated over the next 25 years. In addition, an increasing share of growth is occurring in warmer inland areas of coastal counties.1 Recognizing the water demand that this population growth will bring, water utilities are paying more attention to urban water conservation than ever before. Whereas conservation efforts during the 1990s focused mainly on indoor uses, the focus is now shifting to the outdoors. The policy toolkit includes a host of incentives and technological fixes to encourage residents to water their yards more efficiently and to landscape with low-water plants. To help spearhead these efforts, the legislature recently called for the creation of a Landscape Task Force, composed of stakeholders from the water and landscaping sectors, to evaluate and recommend proposals for improving the efficiency of water use in new and existing urban irrigated landscapes in California. Landscape choices are considered key because Californians—like their neighbors in other semiarid western states—have tended to use plants more suited to humid climates. The typical California lawn, a cool-season turf grass, can require several times more water than native plants. Inefficient watering systems, such as incorrectly timed automatic sprinklers, can significantly compound the problem, creating overwatered lawns and excess water spillage.2 In addition to the resource costs associated with water waste, overwatering generates polluted run-off, which damages rivers, lakes, and coastal waters. 2 P u b l ic P o l ic y I n stit u te of C a l ifor n ia California Economic Policy Lawns and Water Demand in California Land use patterns also matter. Denser development—with more multifamily homes and smaller single-family lots—is typically also more water smart. On a per household basis, multifamily homes use half as much water outdoors as do single-family homes. Among single-family homes, those with larger lots typically use more water for landscaping. This edition of CEP looks at a range of issues related to residential outdoor water use. Drawing on detailed residential housing data, we first assess whether housing patterns are reinforcing or extenuating the pressures posed by California’s demographic shift inland. To determine patterns in outdoor water use, we examine differences across regions and over time in the composition of the housing stock (in particular, the share of multifamily homes) and in the size of single-family lots. We use the reference evapotranspiration rate— a measure of the amount of water required to maintain turf grass in different climatic zones— to estimate the water needs of typical yards across regions. Finally, we assess the potential for key elements in the conservation policy toolkit—including water pricing and various programs to improve irrigation efficiency and encourage the use of lowwater plants—to reduce outdoor water use in different parts of the state. human water use in the state in 2000. California’s cities The urban share has been growing over time; in 1980, it accounted for only 14 percent of the total (Department of Water Resources, 1983). This increase and suburbs used approximately 8.9 million acre-feet of water in 2000, or about 232 gallons is not simply the result of pop- per person per day. ulation growth. Per capita use rose steadily throughout the latter half of the 20th century, with declines setting in only during the 1990s (Figure 1). Average urban per capita use was 185 gallons per day in 1960, 20 percent lower than in 2000. The growth in per capita use probably reflects several factors. One is rising incomes, which tend to increase water demand, in part because of greater demand for water-using appliances (Baumann, Boland, and Hanemann, 1997). A second is resi- dential lot sizes, which, as we shall see, increased over much of this period. A third is the faster rate of population growth in hotter inland areas, where water use is considerably higher. In 2000, inland water use averaged 355 gpcd compared to 195 gpcd along the coast. Even with continued efforts in conservation, total urban water use could grow significantly over Water Use and Population Growth in California According to the Department of Water Resources (DWR) 2005 update of the California Water Plan, California’s cities and suburbs used approximately 8.9 million acre-feet (maf) of water in 2000, or about 232 gallons per capita per day (gpcd).3 This total—often known as the “urban” water demand—includes all residential, commercial, governmental, and industrial uses, with residential uses constituting about twothirds of the whole, or 5.8 maf. In the same year, California’s farmers irrigated an estimated 9.6 million acres of cropland with 34.2 maf of water. Thus, urban uses accounted for 20 percent of total Gallons per capita per day Figure 1. Urban Water Use in California, 1960 to 2000 (gpcd) 400 California Coastal Inland 350 300 250 200 150 100 1960 1967 1972 1980 1985 1990 1995 2000 Sources: Department of Water Resources (1966, 1970, 1974, 1983, 1987, 1994b, 1998, 2005). Notes: “Coastal” includes the North Coast, San Francisco Bay, Central Coast, and South Coast hydrologic regions. “Inland” includes the Sacramento River, San Joaquin River, Tulare Basin, North Lahontan, South Lahontan, and Colorado River hydrologic regions. Although the individual regional classi cations varied somewhat in earlier periods, the broad distinction between coastal and inland is fairly consistent over time. 3P u b l ic P o l ic y I n stit u te of C a l ifor n ia California Economic Policy Lawns and Water Demand in California the coming decades. The California Water Plan’s “current trends” scenario anticipates demand growth by 3.0 maf between 2000 and 2030, despite a projected modest decrease in per capita use, from 232 to 221 gpcd. Southern California’s urban utili- ties will face additional needs because of require- ments to reduce their use of Colorado River water by 0.8 maf. Such levels of demand growth pose consider- able challenges for California’s urban water utili- ties. Most new sources of water are relatively costly, and many options pose risks to the environment because of their effects on wildlife habitat. In prin- ciple, a good deal of urban demand growth could be accommodated by transfers of agricultural water rights to urban users, because agricultural water use is expected to decline as a result of various market forces, includ- Although a majority of ing land development (Depart- California’s population still lives in the two main metropolitan coastal regions . . . forecasts ment of Water Resources, 2005). In practice, transfers are likely to account for only a portion of urban needs because of institutional and logistical constraints suggest that some of the biggest growth pressures in the coming decades will be in hotter (Hanak, 2003). Among other alternatives, the Plan highlights urban conservation as one of the single largest sources of costeffective “new” water to support inland areas. growth.4 Growth Patterns and Outdoor Water Use Because water meters do not generally track indoor and outdoor uses separately, the share of urban water used outdoors can only be estimated. The 2005 California Water Plan estimates that the residential sector used roughly 2.3 maf outdoors in 2000, or 42 percent of total residential demand. Parks, golf courses, and other “large landscapes” used another 0.7 maf.5 (The Plan did not separately estimate outdoor uses for commercial and industrial customers.) The Plan’s estimates for outdoor residential use may be on the low side. One study of a crosssection of 12 U.S. cities found an average outdoor rate of 58 percent (Mayer et al., 1999). California’s Landscape Task Force concluded that outdoor use constitutes about half of residential demand in the state (California Urban Water Conservation Council, 2005). This share can be much lower in milder coastal zones and much higher in hot, dry, desert areas. The water provider for the Las Vegas Valley, located in the Mojave Desert, estimates that roughly 70 percent of residential demand goes to outdoor irrigation.6 Officials in Riverside County estimate that 80 percent of residential water in the Coachella Valley—an area with a similar climate— is used outdoors (Bowles, 2005). Although a majority of California’s population still lives in the two main metropolitan coastal regions—the Los Angeles Basin and the San Francisco Bay Area—forecasts suggest that some of the biggest growth pressures in the coming decades will be in hotter inland areas (Table 1). California’s population is projected to grow by 11.3 million people between 2005 and 2030, and over half of that growth will occur inland—the Sacramento Metro region, the San Joaquin Valley, and the Inland Empire. Residential Lot and Yard Sizes Outdoor water use tends to rise with singlefamily lot sizes, because larger properties have larger yards. County assessor records make it possible to measure lot sizes for singlefamily homes in most of the counties in our main metropolitan regions (for details, see the web-only appendix, http://www.ppic.org/content/other/706EHEP_ web_only_appendix.pdf). We define “yards” as lot size minus the building footprint. Because it is likely that residents with very large lots water a smaller portion of their yards, we have broken these data into small lots (one acre or less) and large lots (between one and 20 acres). Figure 2 presents the cumulative average lot sizes by region for single-family residences 4 P u b l ic P o l ic y I n stit u te of C a l ifor n ia California Economic Policy Lawns and Water Demand in California Table 1. Projected Population Growth in California Regions, 2005–2030 (millions) Region San Francisco Bay Area South Coast Sacramento Metro region San Joaquin Valley Inland Empire Rest of state California Counties Alameda, Contra Costa, Marin, Napa, San Francisco, San Mateo, Santa Clara, Solano, Sonoma Los Angeles, Orange, San Diego, Ventura El Dorado, Placer, Sacramento, Yolo Merced, San Joaquin, Stanislaus, Fresno, Kern, Kings, Madera, Tulare Riverside, San Bernardino Alpine, Amador, Butte, Calaveras, Colusa, Del Norte, Glenn, Humboldt, Imperial, Inyo, Lake, Lassen, Mariposa, Mendocino, Modoc, Mono, Monterey, Nevada, Plumas, San Benito, San Luis Obispo, Santa Barbara, Santa Cruz, Shasta, Sierra, Siskiyou, Sutter, Tehama, Trinity, Tuolumne, Yuba Population, 2005 7.10 17.15 2.04 3.73 3.82 2.98 36.81 Projected Growth, 2005–2030 2.08 2.74 1.37 2.19 2.12 0.80 11.30 Sources: Department of Finance (2004, 2005). Percent of Projected Growth 18.4 24.3 12.1 19.4 18.8 7.1 100 on small lots.7 The San Joaquin Valley is split into two regions to isolate the effects of growth pressures that link its northern end to the Bay Area and its southern end to the population centers in Southern California. As expected, lot sizes are smallest in the region with the highest land prices, the San Francisco Bay Area (7,697 square feet), and they are generally largest in the inland regions, notably the Inland Empire (10,176 square feet) and the Sacramento Metro region (9,515 square feet). What is surprising, however, is the steady upward trend in coastal lot sizes, particularly in Los Angeles and San Diego Counties. Lots in the South Coast (9,076 square feet) are now larger, on average, than those in the northern San Joaquin Valley (8,416 square feet) and nearly as large as those in the southern San Joaquin Valley (9,056 square feet). Because the proportion of homes with more than one story has been on the rise, there has been Square feet Figure 2. Cumulative Average Small Single-Family Lot Sizes by Region 12,000 Inland Empire San Joaquin Valley, south Sacramento Metro San Joaquin Valley, north Southern California Coast San Francisco Bay Area 10,000 8,000 6,000 4,000 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 Source: Authors’ calculations, using county assessor records through 2002. Notes: Data include lots of one acre or less. One acre equals 43,560 square feet. 2000 5P u b l ic P o l ic y I n stit u te of C a l ifor n ia California Economic Policy Lawns and Water Demand in California Despite the recent relatively little increase in average building footprints (estimated as policy attention to denser land use—often known as “smart growth”— California actually built the building size divided by the number of stories), even though home sizes have been steadily increasing.8 Thus, the general patterns for yard sizes are simi- many more multifamily lar to those shown in Figure 2. homes in the 1960s and 1970s than it does today. Meanwhile, lots between one and 20 acres, often called ranchettes, remain an impor- tant component of California’s residential landscape (Figure 3). The shares of these lots are lowest in the two coastal regions and also relatively low in the northern San Joa- quin Valley, which appears increasingly influ- enced by Bay Area housing patterns. Ranchettes average around three acres in size but somewhat higher in the Sacramento region (4.7 acres). They are particularly prominent in some counties— Napa and Sonoma in the Bay Area, El Dorado and Placer in the Sacramento Metro region, Kern in the southern San Joaquin Valley, and San Diego in the South Coast.9 The share of multifamily housing is another important factor in the outdoor water use equa- tion. Because they share common outdoor space, Share (%) Figure 3. Cumulative Share of Large Single-Family Lots by Region 20 Inland Empire San Joaquin Valley, south Southern California Coast Sacramento Metro San Joaquin Valley, north San Francisco Bay Area 15 10 5 0 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 Source: Authors’ calculations, using county assessor records through 2002. Note: Data include lots between one and 20 acres. 2000 multifamily homes use considerably less water outdoors than do single-family residences. Despite the recent policy attention to denser land use—often known as “smart growth”—California actually built many more multifamily homes in the 1960s and 1970s than it does today (Figure 4). Although the share of multifamily housing has increased since 2000, this is mainly a coastal phenomenon. In the hotter inland regions, the overall shares are much lower (Figure 5). As we shall see, these housing trends have a marked effect on outdoor water needs in different parts of the state. Climate Zones and Housing Trends Because hotter climates increase water needs for any given lot size, we reclassified the housing data by climatic zone. These zones are based on evapotranspiration rates for the typical California lawn. Evapotranspiration (ET) is the rate at which plants lose water through evaporation from soil and plant surfaces and transpiration through plant canopies. “Reference evapotranspiration” (ET0) rates provide a measure of the water needed by cool-season turf grass. Thus, ET0 rates give a measure of the baseline water needs of a typical California lawn in different parts of the state. We assigned each Census tract to one of 18 ET0 zones, using maps provided by DWR. For purposes of presentation, we consolidated the 18 zones into four “superzones”: Coastal, Inner Coastal, Central, and Desert (Figure 6).10 The differences across zones are significant. In the Coastal zone, a square foot of cool-season turf grass will require 28 gallons of water or less per year. In the Desert zone, the same patch of grass will need 37 gallons of water or more. The differences are even more pronounced during the dry summer months, when irrigation needs are highest (Figure 6). These evapotranspiration zones provide a much finer breakdown of climatic differences than do regional and county boundaries. Whereas climates 6 P u b l ic P o l ic y I n stit u te of C a l ifor n ia California Economic Policy Lawns and Water Demand in California Share (%) in some regions appear relatively homogeneous (for instance, the Sacramento Metro region and the northern San Joaquin Valley fall entirely within the Central zone), other areas display a great deal of variation. Los Angeles County, for example, spans the entire spectrum from mild coastal to harsh desert climates (for details on individual counties, see the web-only appendix, http://www.ppic.org/content/ other/706EHEP_web_only_appendix.pdf). As of the 2000 Census, 33 percent of the state’s population resided in the Coastal zone, 43 percent in the Inner Coastal zone, 19 percent in the Central zone, and 4 percent in the Desert zone. However, housing production in the Central and Desert zones is growing fast (Figure 7). Nearly 39 percent of the units built in the 1990s were in these two zones, up from 32 percent in the 1980s and just 26 percent in the 1970s. Housing production in the Central zone has now eclipsed production in the Coastal zone. Single-family lots are 60 percent larger in the Desert zone than in the Coastal zone, and large lots are still far more preponderant in the hot inland zones. In addition, the share of multifamily homes recorded by the 2000 Census reads, in inverse order of climate conditions: Coastal (40.1%), Inner Coastal (33.6%), Central (21.1%), and Desert (20.4%). Implications for Outdoor Water Demand Clearly, land use differences across climatic zones appear to be reinforcing the pressures of the demographic shift inland. Despite some signs of inland densification—declines both in lot sizes and in the share of ranchettes—inland areas have lower shares of multifamily homes, higher shares of ranchettes, and higher average lot sizes than does the coast. What do these land use trends mean for outdoor water use? Theoretical Water Needs To get a sense for outdoor water demand, we estimated the average water requirements for cool- Number Figure 4. Statewide Trends in Multifamily Construction, 1940–2004 120,000 100,000 80,000 Multifamily homes built per year (left axis) Share of multifamily homes (right axis) 58% 47% 70 60 50 60,000 30% 40,000 19% 30% 23% 40 28% 30 20 20,000 10 00 1940–50 1950–60 1960–70 1970–80 1980–90 1990–2000 2000–04 Sources: Authors’ calculations, using data from the Census (1940–2000) (changes in housing stock) and the Construction Industry Research Board (2004) (housing permits). Notes: The multifamily category includes structures with two or more residential units; it excludes both detached and undetached single-family homes. Data exclude “other” housing categories, such as mobile homes and boats. Figure 5. Regional Shares of Multifamily Homes in Housing Stock and New Construction 50 44 40 35 30 20 10 47 38 Housing stock, early 2000 New construction, 2000–04 19 14 20 9 24 18 0 Bay Area South Coast Inland Empire San Joaquin Sacramento Valley Metro Source: Authors’ calculations, using the 2000 Census (stock) and Construction Industry Research Board (permits). Share (%) season turf grass, our ET0 crop. Table 2 provides these estimates for small single-family lots by region and by ET0 superzone. We assume that households irrigate 35 percent of their yard, with the remainder covered either in hardscape or in non-irrigated landscape.11 Across regions, this amounts to an average irrigated area in the range of 2,000 to 3,600 square feet. Average water requirements are obtained by multiplying this area by average ET0 rates.12 7P u b l ic P o l ic y I n stit u te of C a l ifor n ia California Economic Policy Lawns and Water Demand in California Number Figure 6. Evapotranspiration “Superzones” Summer water requirements (turf grass) (monthly gallons per square foot) Coastal (2.6–3.6) Inner Coastal (3.7–4.2) Central (4.3–4.7) Desert (5.0–5.4) Figure 7. Units Built by Decade by ET0 Superzone 1,200,000 Coastal Inner Coastal Central 1,000,000 800,000 600,000 400,000 200,000 0 1940 1950 1960 1970 1980 Source: Authors’ calculations based on the 2000 Census. Note: Includes all California counties. Desert 1990 2000 Because of larger lot sizes and drier climates, the amount of water lost through evapotranspiration from a typical grass lawn is much greater in California’s inland areas. In the Coastal zone, a typical single-family lawn requires 0.17 acre-feet per year, whereas its Desert zone counterpart needs nearly three times as much. With some additional assumptions, we can apply this same framework to the entire housing stock, incorporating ranchettes and multifamily lots (Table 3). For ranchettes, we assume only 10 percent irrigated landscaping, corresponding to an average area of roughly one-quarter of an acre.13 For multifamily homes, we assume that outdoor water use is half the single-family average.14 These estimates imply that California households irrigated a total of just under 633,000 acres in 2000.15 For the most part, incorporating these additional housing stock characteristics exacerbates the differences in regional water needs described in Table 2. Water needs decrease in the Bay Area and the South Coast and in the corresponding climatic zones (Coastal and Inner Coastal)—a benefit of the high share of multifamily homes. Elsewhere, the effect of large lots dominates. This effect is most striking for the Sacramento Metro region, where ranchettes are most common: The average household’s outdoor water needs increase by 60 percent. For the Central and Desert zones as a whole, these needs increase by 20 to 30 percent. Water requirements in these zones are more than two to three times greater than on the coast. Because climate and land use are working in the same direction, it is useful to see how much each factor contributes to these regional differences. Figure 8 compares estimated water needs in inland zones with the water needs these zones would face if they shared the more compact housing patterns of the coast. Actual land use patterns account for a substantially greater share of the additional water needs than climate does. In the Central and Desert zones, land use—not climate—is the clear driver, accounting for four-fifths of the total increase relative to the Coastal zone. Recent changes in land use may be shifting outdoor water needs. To track this trend, we compared the water needs of homes built between 1991 and 2000 with the needs of the 1990 housing stock. Figure 9 shows these comparisons, with new housing needs expressed as a percentage of the needs of homes already built by 1990. To isolate the effects of lot size and composition, we applied the ET0 rates for older homes to the new housing. For single-family homes of one acre or less, denser tract development in the four inland regions 8 P u b l ic P o l ic y I n stit u te of C a l ifor n ia California Economic Policy Lawns and Water Demand in California Table 2. Average Water Requirements of Turf Grass for Small Single-Family Lots Region Yard Size (square feet) Weighted Average ET0 (inches/year) Annual Water Requirements (acre-feet) San Francisco Bay Area 6,308 45.9 0.19 South Coast 7,623 49.8 0.25 San Joaquin Valley, north 7,060 54.4 0.26 San Joaquin Valley, south 7,711 56.2 0.29 Sacramento Metro region 8,129 56.8 0.31 Inland Empire 8,858 56.2 0.33 ET0 zone Coastal 6,019 42.6 0.17 Inner Coastal 7,930 51.9 0.28 Central 7,687 56.0 0.29 Desert 10,349 66.7 0.46 % Increase over Region with Lowest Need — 31 33 50 59 72 — 60 68 169 Table 3. Average Water Requirements of Turf Grass for Residential Lots Small Single-Family Lots Large Single-Family Lots Multifamily Lots Region % of Average % of Average All Yard Size All Yard Size Lots (square feet) Lots (square feet) % of All Lots San Francisco Bay Area 61.2 6,308 2.8 139,855 36.0 South Coast 59.1 7,623 1.6 119,824 39.3 San Joaquin Valley, north 76.1 7,060 3.7 134,766 20.2 San Joaquin Valley, south 67.8 7,711 7.4 152,849 24.8 Sacramento Metro region 63.8 8,129 11.5 203,920 24.7 Inland Empire 74.6 8,858 4.7 127,035 20.7 ET0 zone Coastal 58.7 6,019 1.1 127,382 40.1 Inner Coastal 64.4 7,930 2.0 111,147 33.6 Central 71.4 7,687 7.5 175,058 21.1 Desert 70.0 10,349 9.6 144,556 20.4 Average Annual Water Requirements Acre-Feet per Household % Increase over Region with Lowest Need 0.19 — 0.22 16 0.27 46 0.36 89 0.50 165 0.35 85 0.15 — 0.25 67 0.38 158 0.55 276 9P u b l ic P o l ic y I n stit u te of C a l ifor n ia California Economic Policy Lawns and Water Demand in California Annual water needs per household (acre-feet) Water needs of 1990 housing stock = 100 Figure 8. Effects of Climate and Land Use on Outdoor Water Needs of Turf Grass 0.60 Water needs with coastal land use Incremental needs related to actual land use 0.50 0.40 0.30 0.20 0.10 0.00 Coastal Inner Coastal Central Desert Figure 9. Comparison of Outdoor Water Needs for Homes Built During the 1990s and Older Homes 180 160 140 120 100 100 107 80 163 141 Small single-family lots All residential lots 102 90 93 87 85 91 122 91 60 40 20 0 Bay Area South Coast San Joaquin San Joaquin Inland Sacramento Valley, north Valley, south Empire Metro Note: Calculations use 1990 average evapotranspiration rates to control for the effect of changes in the location of new housing. has reduced landscape water needs for new homes by 9 to 15 percent compared to the older housing stock. The opposite is true in the South Coast, where single-family lots have been getting larger. The picture changes somewhat when we take into account all types of new housing combined. Some of the inland savings disappear, and water needs increase substantially in the South Coast and in the Sacramento Metro region. One factor is the declining share in new construction of multifam- ily housing in the 1990s, which occurred in every region. But an even bigger factor is the growing role of large lots. They rose slightly as a share of all housing in three regions (Sacramento Metro, South Coast, and the Bay Area), and they increased in average size everywhere. For the South Coast, the overall result is a profile of new housing with potential landscape water needs over 60 percent above the level in 1990. In the Bay Area and the South Coast, these needs have also increased somewhat because newer housing has located in warmer areas.16 These trends have reduced some of the differences in water needs between coastal and inland regions. Actual Water Needs Of course, these figures provide only a “guesstimate” of households’ actual outdoor water use. In practice, there is considerable variation in the proportion of yards that are watered, and not everyone plants only cool-season turf grass, our baseline crop.17 Moreover, irrigation practices can differ widely. The ET0 rates for turf grass allow for a lush, thick lawn, several inches high. In practice, experts assume that residential lawns can get by with about 80 percent of the ET0 requirements.18 However, the ET0 rates also assume that no water is wasted, either in making the ground soggy or in spilling onto sidewalks and streets. Such wastage results in a level of irrigation efficiency—the share of water actually used by the plant—below 100 percent. Many residences and businesses still fall well below the existing statewide standard for landscape irrigation efficiency of 62.5 percent. The amount of water a plant actually needs (sometimes known as the “ET adjustment factor”) can be summarized in this fashion: ET adjustment factor = plant’s ET requirement irrigation efficiency rate Thus, a residential lawn with an 80 percent ET requirement, irrigated at 80 percent efficiency, needs 100 percent of its baseline water needs (the ET0). If irrigation efficiency is lower, the actual water 10 P u b l ic P o l ic y I n stit u te of C a l ifor n ia California Economic Policy Lawns and Water Demand in California Table 4. Landscape Water Needs with Different Plant Types and Irrigation Efficiencies Average Plant ET Requirement Irrigation Efficiency 50% 62% 70% 80% High Water (80%) 160 129 114 100 Medium Water (50%) 100 81 71 63 Low Water (20%) 40 32 29 25 50% High 50% Medium (65%) 130 105 93 81 Note: Numbers are expressed as a percentage of reference evapotranspiration. a1/3:1/3:1/3 denotes a mix of one-third each high-, medium-, and low-water-using plants. 1/3:1/3:1/3a (50%) 100 80 71 62 needed is greater than 100 percent. If it is higher, or if the plant mix is less thirsty, the actual water needed falls below 100 percent. Table 4 summarizes this relationship for some benchmark plant types and irrigation efficiency rates. Cool-season turf is a typical high-water-using plant. (Warm-season turf grass, still not very common in California, has an ET requirement of 60 percent.) Various landscape alternatives, including shrubs and trees, fall into the medium category, and many native species are low water users. A conventional residential mix might be half cool-season grass and half trees and shrubs, for an overall ET requirement of 65 percent.19 Using California’s irrigation efficiency standard of 62.5 percent, such a yard would require 105 percent of the ET0 shown in Tables 2 and 3. We estimate that the average for California yards in 2000 was in the range of 106 to 127 percent of the ET0.20 In a normal year, rainfall during the cooler winter months can generally cover about a quarter of these needs, and the balance must be made up with irrigation. In dry years, which are no stranger to California, landscape water needs are typically higher. Because supplies are also scarcer in such times, droughts often lead utilities to impose outdoor watering restrictions. Looking ahead, there is a strong possibility that climate warming will increase plant water needs in California—particularly in the hotter inland areas, where average temperatures are predicted to rise considerably (Hayhoe et al., 2004). Climate change is also expected to put greater pressures on water supplies by reducing the amount of water stored in the Sierra Nevada snowpack.21 These shifts will Smart growth land use mixes that achieve higher density can truly be water smart. However, most approaches to outdoor conservation raise the importance of efforts to curb outdoor water use. focus on ways to reduce water use with existing land use patterns. Conservation Strategies As the preceding analysis makes clear, land use patterns can have a tremendous effect on the potential outdoor water needs of the residential sector. Smart growth land use mixes that achieve higher density can truly be water smart. However, most approaches to outdoor conservation focus on ways to reduce water use with existing land use patterns. The following four strategies provide different paths toward water-smart yard mainte- nance and greater outdoor water conservation. Water Pricing One overarching tool that is gaining renewed attention is water pricing. There are four general kinds of rate structures: flat, declining block, uniform, and 11P u b l ic P o l ic y I n stit u te of C a l ifor n ia California Economic Policy Lawns and Water Demand in California increasing block. Flat water rates—which do not vary by the amount of water used—are still com- mon in the Central Valley, much of which remains unmetered. Declining block rates, which essentially offer a bulk discount to heavy water users, are now rare. Most residential lots in California are subject to uniform rates—which charge the same amount for every gallon—or increasing block rates—which charge more per gallon for higher levels of use (Hanak, 2005). (Seasonal pricing, under which rates are increased during the summer months of peak demand, is rarely used in California.) Since 1991, the California Urban Water Conservation Council has encouraged the adoption of “conserva- tion pricing”—with rates set as close as possible to the utility’s own long-run marginal cost of water, using either uniform or increasing block rates.22 Although water is a relatively “inelastic” com- modity, recent evidence suggests that consumers are more sensitive to water prices than previously thought.23 It appears that price sensitivity is higher when customers face increasing block rates rather than uniform rates.24 Custom- ers also appear to be more sen- Although water is a relatively “inelastic” commodity, recent evidence suggests that sitive to prices for outdoor than indoor uses (Mansur and Olmstead, 2006). These findings suggest that increasing block rate structures may be better than consumers are more sensitive to water prices than previously thought. uniform rates at encouraging conservation—and that pricing can be an especially important outdoor conservation tool. (Flat rates, in contrast, offer no incen- tive to conserve.) Increasing block rate structures also have a built-in equity component, given that larger lots and higher water use within an area are generally associated with higher-income house- holds. To see how water rate structures interact with residential land use patterns, we matched our single-family lot data with water rate data for the four-fifths of our sample residing within the ser- vice areas of large utilities (Table 5).25 As the table makes clear, water rates are least conducive to conservation in some of the state’s hottest areas. However, flat and declining rate structures do not appear to be encouraging larger average lot sizes; lots are actually largest in the Central and Desert zone communities with increasing block rates.26 Increasing block rate structures are most prevalent in the Coastal and Inner Coastal zones, where water authorities have been more active in statewide conservation programs. Many utilities adopted these rate structures following the early 1990s drought. However, there has been little progress in shifting to increasing block rate structures or away from flat rate structures since the mid-1990s (Hanak, 2005). Recent efforts to put conservation pricing back on the front burner come from two quarters. One is the Landscape Task Force, which developed new conservation pricing guidelines to encourage utilities to send more accurate price signals to customers.27 The other is the California legislature, which has been pushing utilities with flat rates to convert to metering. After more than a decade of political wrangling, the legislature passed AB 2572 in 2004, which requires that all utilities with 3,000 or more customers install meters over the next two decades and begin using installed meters for billing by 2010. (Since 1992, builders have been required to install meters in new homes, but utilities have not been required to read them.) Some communities are starting to see the potential conservation benefits of this change: For instance, the fast-growing town of Lodi aims to finish installing meters long before the 2024 deadline, to realize conservation savings sooner (Hood, 2005). Smart Sprinklers Automatic sprinkling systems are popular because they are more convenient than manually operated hoses or sprinklers. The problem is that they often operate for too long or at times when watering is not needed. (As a rule of thumb, these systems operate with an irrigation efficiency rate of 50 percent or less.28) Rather than encourage people to go back to manual systems, many utilities are looking to address this problem by promoting “ET” or 12 P u b l ic P o l ic y I n stit u te of C a l ifor n ia California Economic Policy Lawns and Water Demand in California Table 5. Average Small Single-Family Lot Sizes by Water Rate Type Flat Declining Block Uniform Increasing Block ET0 Superzone Coastal Inner Coastal Average % of Average % of Average % of Average % of (square feet) Lots (square feet) Lots (square feet) Lots (square feet) Lots 7,617 0 16,711 0 7,202 43 7,327 57 n/a 0 10,913 0 8,905 44 9,351 56 Central Desert 8,306 9,429 49 2 8,266 n/a 6 8,051 29 10,083 16 0 10,929 62 11,709 37 Total 8,308 7 8,324 1 8,396 42 8,727 50 Source: Authors’ calculations, using county assessor records through 2002. Notes: Percentages show the share of homes in each climatic zone with each type of rate structure. Data include lots of one acre or less. “smart” irrigation controllers, which automatically adjust watering times based on plant cover and weather conditions. Smart controllers can operate either with on-site weather sensors or with communication links to a centralized weather-monitoring system.29 Previously limited to large commercial or public landscapes, smart controllers are now available to residential customers through rebate programs in several water districts. Field studies have shown that smart controllers can reduce residential water use considerably. In 2000, the Irvine Ranch Water District (IRWD) retrofitted 33 high-water-using homes with ET controllers.30 After two years, these homes had reduced their total water consumption by 41 gallons per household per day—approximately 18 percent of outdoor water use. In 2002, several water districts targeted high residential water users in Santa Barbara County. By 2003, 62 customers had switched to ET controllers, and preliminary results indicate that their average total water use has gone down by 26 percent.31 The Metropolitan Water District of Southern California (MWDSC), the large wholesale utility serving much of Southern California, estimates that smart controllers, in conjunction with highly efficient spray nozzles, could reduce outdoor residential water use by 28 percent within its service area.32 If ET controllers can save this much water, are they a good investment? To find out, we calculated the cost of saving water in different regions, using the savings rates obtained in field trials. Table 6 presents consumer and utility costs under some different scenarios. The calculations assume the use of a new, smart controller in a typical small lot in each of the four climatic zones, currently planted half turf and half shrubs and trees and being watered at 50 percent irrigation efficiency.33 The top panel of the table shows scenarios for water savings and customer costs. For the cost of the ET controller itself, the “low” alternative is for purchase and professional installation of an on-site sensor system and the “high” alternative is for a satellite system, which has a higher up-front cost and a monthly subscription fee.34 These costs are shown spread out over 15 years (the estimated life of the controller), both with and without utility rebates of $180 to $220 per system.35 The table’s bottom panel shows the water costs to utilities and the potential water bill savings for customers. Utility costs are expressed as the investment costs of procuring this “new” water through the rebate program, again on the assumption that the savings are available for only 15 years. We include an allowance for administrative costs.36 For consumers, the best bet is likely to be controllers with on-site sensors. With the utility subsidy, these systems generate enough savings on the water bill to more than cover the $9 in annualized costs, even with lower efficiency gains and in places with 13P u b l ic P o l ic y I n stit u te of C a l ifor n ia California Economic Policy Lawns and Water Demand in California Table 6. Smart Controller Costs and Savings ET Superzone Coastal Inner Coastal Central Desert Water Savings (gallons per day per household) Low (15%) High (25%) 22 37 36 60 38 63 60 101 Costs to Utility ($/acre-foot) Inputs Full cost After rebate Annual Cost to Customer (per controller) Low (on-site) High (satellite) $26 $95 $9 $79 Outputs Annual Savings to Customer (per controller) Low Water Price ($242/acre-foot) High Water Price ($678/acre-foot) ET Superzone Coastal Inner Coastal Central Desert Low Water Savings 584 397 379 256 High Water Savings 350 238 228 154 Low Water Savings 6 10 10 16 High Water Savings 17 27 29 46 Low Water Savings 10 16 17 27 High Water Savings 28 46 48 76 Notes: Assumes that 25 percent of water needs is met by rainfall. Both utility and customer investments are amortized at a rate of 4 percent. low water prices (the sole exception is low prices and low savings in the Coastal zone).37 Meanwhile, it is hard to break even with the satellite-linked systems, which cost $79 after rebate, mainly because it is harder to cover the on-going subscription costs (now $48 per year) through water bill savings. For utilities, the calculus involves comparing the costs of water procured through the rebate program with the costs of alternative sources. By this yardstick, these rebate programs have the potential to be cost effective. As a point of comparison, desalinated water has estimated annual costs in the range of $800 to $1,500 per acre foot, and average costs for recycled wastewater are estimated at $600 (Department of Water Resources, 2003a, 2003b).38 For both customers and utilities, savings would improve under rebate programs targeting high water users—those with particularly low irrigation efficiency, larger yards, and a higher share of turf in their overall yard mix. For customers, the sav- ings would also improve if ET controllers reduce other costs (e.g., less wastage of fertilizers and pesticides from overwatering).39 To the extent that ET controllers also help curb urban run-off, these programs can bring additional local benefits in pollution control.40 However, smart controllers do not address other sprinkler system problems, such as incorrectly set valves or sprinkler heads or other inefficiencies in the layout of the system. For this reason, consumer education needs to accompany these programs. Water-Wise Landscapes Water consumption can also be greatly reduced through the use of drought-tolerant plants. Throughout the American West, utilities have promoted “water-wise” landscaping since the mid-1990s. Outreach efforts have focused not only on educating people about the water savings potential but also on the attractiveness of these landscapes, which 14 P u b l ic P o l ic y I n stit u te of C a l ifor n ia California Economic Policy Lawns and Water Demand in California include many beautiful, flowering plants, not just prickly cacti and rocks. Because plant availability can be a problem, utilities have begun locating their demonstration gardens at home and garden stores. The hope is that this will encourage major retailers like Home Depot to stock native plants, which they have begun doing only recently. Consumer education can be a major undertaking. Since 2002, MWDSC has spent more than $6 million on advertisements to promote “California friendly” landscaping, designed to reduce overwatering and encourage the use of native plants.41 To add teeth to these efforts, some water districts have launched turf buy-back programs, or socalled “cash-for-grass” initiatives. Through these programs, utilities pay customers to replace turf with less water-intensive plants and to install drip irrigation. Rebates range from $0.40 per square foot in Victorville, California, to $1 per square foot in Las Vegas, Nevada. These rebates cover only a portion of the cost to the consumer to replace turf. The Southern Nevada Water Authority (SNWA), which runs the Las Vegas program, estimates that customers pay from $2 to $5 per square foot to convert their landscapes.42 The potential water savings come from the combined effect of lower plant needs and higher irrigation efficiency, and they are truly spectacular. Well-installed drip irrigation can attain efficiency levels approaching 90 to 95 percent, and low-water plants need only 20 percent of the ET0 rate (compared to 80 percent for lawns). A conversion of a cool-season turf lawn using a “dumb” automatic sprinkler system to a “smart” drip-irrigated garden with drought-tolerant plants could move overall plant needs from 160 percent to as low as 21 percent (Table 4). Although the savings in practice are more modest, they are nevertheless considerable. Drawing on detailed field surveys, SNWA estimates that conversion from turf to low-water landscaping brought water use down from 73.0 gallons of water per square foot to just 17.2 gallons per square foot, a 76 percent savings.43 The agency has encouraged residential customers to go for varied landscapes, keeping turf grass in places where they actually use it. Between 2001 In Las Vegas, conversion and 2005, SNWA bought back over 1,500 acres of turf, or over 11,300 acre-feet of water. Purchases went up dramatically in 2003, when the rebate was raised from turf to low-water landscaping brought water use down from 73.0 gallons of water per from $0.40 to $1.00 per square square foot to just 17.2 foot. How might such a program fare in California? Table 7 com- gallons per square foot, a 76 percent savings. pares the costs to utilities and customers of turf buy-back programs across Cali- fornia’s climate zones, assuming water savings sim- ilar to that in Las Vegas (76%). To calculate these savings, we assume lower irrigation efficiency than in the smart controller example above (37.5% ver- sus 50%).44 Water savings and costs are shown per square foot, so that the only variation across zones is due to climate. Utility costs assume 15 years of savings, as above. For customers, costs are shown in terms of the number of years needed to recoup the net investment, assuming a total conversion cost ranging between $2 and $2.60 per square foot. The three payback scenarios reflect different assumptions about the savings from conversions: (1) savings on the water bill only, (2) additional savings from lower expenditures on garden sup- plies, and (3) additional savings from lower labor expenditures on garden maintenance. These “non- water” savings are drawn from a survey in the Las Vegas area, which found that homes with a greater proportion of lawns had higher labor and supply costs for mowing and other aspects of lawn main- tenance.45 It must be stressed that these results may not be representative. For consumers, the water savings alone are un- likely to be a significant draw, even with a generous utility rebate. The picture changes dramatically, however, if homeowners reap additional savings in terms of lower garden supply and labor costs. These savings even make conversion a potentially attrac- tive proposition in coastal areas and with higher net costs. These very different results underscore the importance of improving our understanding of 15P u b l ic P o l ic y I n stit u te of C a l ifor n ia California Economic Policy Lawns and Water Demand in California Table 7. Turf Conversion Costs and Savings Customer Years to Recoup Investment Low Net Conversion Costs ($1.00/square foot) ET0 Superzone Coastal Inner Coastal Water Savings (gallons/square foot) 32 39 I II III 23 6 3 17 6 2 Central Desert 42 51 15 5 2 12 5 2 Costs to Utility ($/acre-foot) High Net Conversion Costs ($1.60/square foot) Low Rebate ($0.40/square foot) High Rebate ($1.00/square foot) I II III Coastal 363 907 76 10 4 Inner Coastal 298 745 38 10 4 Central 276 690 32 9 4 Desert 232 580 23 8 4 Notes: Assumes a retail water price of $678 per acre-foot. Scenario I includes only water savings, scenario II also includes garden supply savings, and scenario III includes labor cost savings. Both utility and customer investments are amortized at a rate of 4 percent. Baseline irrigation efficiency is 37.5 percent, with 25 percent of plant water needs met by rainfall (or alternatively, 50% irrigation efficiency with no rainfall contribution). the total costs of landscape alternatives to households, not just the water savings. For utilities, purchasing water through a cash-for-grass program appears to be a considerably more expensive proposition than the rebate program for smart controllers, particularly at the price of $1 per square foot and in the milder climate zones. Actual costs may be higher, as we have not included the costs of program administration and we have assumed very high rates of water savings. If, on the other hand, the program creates a permanent shift in landscaping habits, rather than the 15 years assumed here, this would lower costs by about a third. As with smart controllers, there are additional benefits in control of polluted run-off. Regulating Landscapes In addition to public education and rebate programs, which aim to change tastes and behavior through voluntary means, some localities are emphasizing regulations. Such policies typically take the form of local ordinances, and they target landscaping practices in public, commercial, and residential areas. In California, the initial push for landscape regulations came from the state legislature, during the early 1990s drought. In 1990, the Water Conservation in Landscaping Act (AB 325) required that DWR draft a model waterefficient landscape ordinance. The model ordinance contained a number of stipulations involving irrigation design and efficiency and the use of native plants.46 It applied to large commercial and public landscapes and to residential landscapes installed by developers. Local agencies were required to adopt the model ordinance, adopt their own ordinance, or issue legal findings that they did not need an ordinance. Although most cities and counties complied with the statute, actual implementation of the local ordinances has been inconsistent, and program monitoring has been minimal (Bamezai, Perry, and Pryor, 2001). 16 P u b l ic P o l ic y I n stit u te of C a l ifor n ia California Economic Policy Lawns and Water Demand in California Some of the most enthusiastic local adopters are in fast-growing inland areas of Southern California. Many towns now require that developers use “California friendly” plants in all road medians and other public spaces. The City of Lancaster, for example, located in a hot area of eastern Los Angeles County, requires that all public landscaping be drought-tolerant. Several desert cities and utilities have adopted more widely applicable landscape ordinances. The Coachella Valley Water District (2003) recently adopted an ordinance requiring that new and refurbished landscaping feature vegetation that uses 25 percent less water than that required by the model ordinance. Other localities are taking the lead from cities in neighboring southwestern states, where landscaping restrictions have become increasingly common. In weighing the pros and cons of landscape regulation, it is important to consider the value of lawns to households and communities. To the extent that lawns provide recreational space, lowwater plants, no matter how beautiful, are not a good substitute. Even though common area lawns may be a more efficient way to provide this space, many households may prefer to have their own lawns for privacy and safety reasons. These considerations suggest that cost savings alone will not be enough to motivate all residents to make the switch. Encouraging people to cut back on turf in places where they do not use it—such as front yards and median strips—may be a more effective strategy than encouraging wholesale lawn removal.47 What Role for State Policy? Many outdoor conservation policies stem from local and regional initiatives, but the state has not been absent from the scene. Various rebate programs are supported by state grants, state legislation provided the impetus for landscape ordinances, and legislation now requires that utilities start using meters to bill for water use. The recommendations of the Landscape Task Force, presented to the governor and the legislature in December 2005, call for the state to play a greater role in the future. The report contains 43 recommendations covering a wide range of actions (California Urban Water Conservation Council, 2005). In addition to stressing the importance of rate structure reform and more education and training, the recommen- dations focus on regulatory approaches: requiring smart irrigation controllers and dedicated land- scape meters, adopting and enforcing statewide prohibitions on overspray and runoff, and strengthening and enforcing compliance with landscape ordinances. They also call for improvements in the knowledge base on irrigation requirements and plant water needs in Outdoor water conservation will need to be an important policy focus in many parts of the state, different parts of the state. This both to limit increases includes extending the California Irrigation Management Information System (CIMIS)—a network of weather stations designed to gauge irrigation needs—to more in water demand and to free up water supplies to accommodate new residents. urban areas. The emphasis on regulation parallels the estab- lished approach to indoor conservation; state and federal regulations on plumbing fixtures and appli- ances are widely viewed as central to the successes achieved to date. For the outdoor environment, where there is considerably more variability in the potential for water savings, it will be especially im- portant to weigh the costs and benefits to house- holds and to society before imposing regulatory solutions. As with indoor appliances, regulations focusing on new construction may have the great- est potential to achieve a beneficial outcome. Conclusion The magnitude and geographical distribution of population growth in California are poised to exert significant pressure on the state’s water delivery systems over the coming decades. Outdoor water conservation will need to be an important policy focus in many parts of the state, both to limit increases in water demand and to free up water supplies to accommodate new 17P u b l ic P o l ic y I n stit u te of C a l ifor n ia California Economic Policy Lawns and Water Demand in California residents. Key elements of the policy toolkit include water rate reform; the use of new, “smart” watering methods; and landscaping changes that reduce water use. Many utilities are focusing on education and outreach to provide households with information on alternatives and to make low-water plants more readily available at nurseries. Some are proposing rebates. Regulatory restrictions on landscaping of new homes—restricting lawns to a fraction of the yard—are still rare in California but increasingly common in neighboring states. Our analysis suggests that rebates to homeowners may be a costeffective way to improve irrigation systems, particularly in the hotter, dryer regions and when water prices are higher. The savings from replacing turf with low-water plants are less obvious. For new homes, it may be easier (and more cost-effective) to build “water smart” from the ground up. Whether education and outreach (particularly with builders) is sufficient to encourage this goal, or whether regulatory solutions are required, is still an open question. Conservation-oriented water rates, which signal water scarcity to households, should be a part of any conservation package. v Notes 1 An analysis of 2000 Census housing data by tract reveals that the average “reference evapotranspiration rate”—a measure of plant water needs resulting from climate— increased significantly in both the San Francisco Bay Area and the South Coast region for housing built since 1980. See the discussion on evapotranspiration zones. For trends in individual counties, see the web-only data box, http://www. ppic.org/content/other/706EHEP_web_only_appendix.pdf. 2 For a sample of 1,129 households with sprinklers, Maddaus and Mayer (2001) found that the addition of an automatic sprinkler increased outdoor use by 55 to 60 percent. In the hotter zones, 57 percent of surveyed homes used these systems compared to 20 percent in the cooler, wetter climates. 3 An acre-foot of water is equivalent to 325,851 gallons, the amount of water it takes to cover an acre of land one foot deep. One acre-foot is the amount of water used annually by five to eight people. 4 The Plan cites several studies suggesting the potential for significant, cost-effective savings. A Pacific Institute study (Gleick et al., 2003) estimated that urban water use could be reduced by roughly 12 percent at a cost of $100 per acre-foot or less and by as much as a third at less than $600 per acre-foot (the benchmark price used by the study authors for alternative sources). The California Urban Water Agencies (2001, 2004) estimate that implementation of quantifiable “best management practices” (a narrower set of goals) would generate just over one million acre-feet cost-effectively by 2030. A study for the California Bay Delta Authority (2005) estimates a savings potential of up to 3.1 million acre-feet, although the last million might not be cost-effective. 5 Measurement of water use in the “large landscape” category is more precise, thanks to separate meters. 6 See http://www.snwa.com/html/cons_waterfacts.html. 7 Although the graph only shows trends back to 1945, the cumulative average extends back to the earliest records, as early as 1803 in the South Coast. 8 Single-family home sizes in California grew from an average of 1,277 square feet in the mid 1940s to nearly 2,600 square feet by the early 2000s. Building footprints increased from roughly 1,200 square feet to 1,900 square feet over this interval. It is possible that the total amount of hardscape—including garage area and pavement, in addition to the home’s footprint—has increased by a greater amount, but we have no way to measure this. 9 Because the data on lot sizes are less precise for some of these counties, it is possible that our analysis overstates the importance of these lots in the overall picture. Also, some of these ranchettes may be hobby farms or vineyards, for which water use would fall within agricultural demand. 18 P u b l ic P o l ic y I n stit u te of C a l ifor n ia California Economic Policy Lawns and Water Demand in California 10 The Coastal superzone includes ET0 zones 1 through 5, the Inner Coastal superzone includes ET0 zones 6 through 10, the Central superzone includes ET0 zones 11 through 15, and the Desert superzone includes ET0 zones 16 through 18. 11 This percentage is in line with recent field studies by the East Bay Municipal Utility District (EBMUD). In a 1995 survey, an average of 2,513 square feet, or 26 percent of the total lot, was irrigated—corresponding to roughly 31 percent of our definition of yard (Opitz and Hauer, 1995). In a 2001 survey, average irrigated area was estimated as roughly the same (2,510 square feet), but no total lot size was given (Water Resources Engineering, Inc., 2002). Our estimates from county assessor records suggest that this corresponds to roughly 36 percent of total lot size. 12 The weighted average ET0 for each region and superzone is calculated based on the number of lots in each of the 18 detailed ET zones. The numbers shown here reflect regional and zonal ET0 using the distribution of single-family homes in the county assessor records. The results are nearly identical when we use the rates calculated from the distribution of homes in the 2000 Census. 13 We also evaluated higher percentages, but these implied far too much aggregate outdoor residential water demand relative to DWR’s estimates of total residential use. 14 This estimate is derived using the 2000 Census estimate of the share of multifamily units in the total (32.9%) and DWR’s estimate that multifamily units accounted for 26.8 percent of residential water use in that year (see Department of Water Resources, 2004). For that same year, DWR (2005) estimates average indoor residential use at 3,233,000 acre-feet, or 0.28 acre-feet per household, and average outdoor use at 2,328,000 acre-feet. If average multifamily and single-family indoor use is the same, this implies an average single-family outdoor use of 0.24 acrefeet and average multifamily outdoor use of 0.11 acre-feet, 46 percent of the single-family value. We apply a rate of 50 percent, because it is also likely that multifamily homes have somewhat lower indoor use. Note that these ratios are similar to those found by Dzieglielewski et al. (1990) in a study conducted in Southern California (Department of Water Resources, 1994a). 15 The estimates are obtained by multiplying the average lot sizes in each ET0 superzone by the volume of single and multifamily housing reported in the 2000 Census. 16 The additional effect of shifts in the average ET0 rate was a 7 percent increase in the Bay Area and a 3 percent increase in the South Coast. In the inland regions, the increases are under 1 percent. 17 A recent survey of single-family homes in the EBMUD service area found, for instance, that roughly a quarter of all households had no irrigated landscape in the front or back yard (Water Resources Engineering, Inc., 2002). 18 This is the standard for cool-season turf grass embodied in California’s Model Landscape Ordinance, for instance. 19 In the EBMUD studies, lawns accounted for about 40 percent of the irrigated landscape (Opitz and Hauer, 1995; Water Resources Engineering, Inc., 2002). The Metropolitan Water District of Southern California’s outdoor water conservation programs assume that a conventional landscape consists of 60 percent lawn and 40 percent shrubs and trees. 20 We obtained these figures by comparing outdoor water use estimates in the inland and coastal areas with our estimates of irrigated acreage and assuming that 25 percent of plant water needs are covered by rainfall. With DWR’s estimate of outdoor residential water use (2.3 million acrefeet, or 42 percent of all residential use), we obtain an ET factor of 106. If outdoor use instead made up half of the residential total, the ET factor jumps to 127. Rates are higher in the inland regions in both scenarios. 21 Hayhoe et al. (2004); Lund et al. (2003); Department of Water Resources (2005). 22 The long-run marginal cost is the incremental per unit cost of expanding water supply, taking into account both investment and operational costs. 23 In part, this new view stems from improved estimation techniques, which better capture the effect of fixed fees and jumps in prices associated with increasing block rates. See Hanemann and Hewitt (1995). 24 In a study based on a climatically and geographically diverse dataset, Olmstead, Hanemann, and Stavins (2005) find that households subject to increasing block rate water prices exhibit nearly double the price elasticity of houses subject to uniform pricing structures. The study found a price elasticity of –0.64 for increasing block rate households versus –0.33 for uniform pricing households. In a meta-analysis incorporating over 300 estimates of water price elasticity, Dalhuisen et al. (2003) also found greater price sensitivity under increasing block rate systems. 25 The data on rate structures are from Black and Veatch (2001, 2003) and phone surveys. The sample included 348 utilities meeting the size threshold for the Urban Water Management Plans Act (at least 3,000 customers or 3,000 acre-feet of annual water sales). 26 In particular, this group includes water districts in the Sacramento Metro region, the Inland Empire, and Los Angeles County. Most switched from uniform to increasing block rates in the early to mid-1990s. 27 In practice, this is proposed through benchmark shares of volumetric pricing in total revenues. To qualify as conservation pricing, 60 percent of total revenue through a tiered rate structure must come from volumetric revenue (as opposed to revenue from fixed charges). For uniform rate structures, volumetric revenue must constitute at least 75 of total revenue. See California Urban Water Conservation Council (2005). 28 This is the rate the Metropolitan Water District of Southern California is assuming in its estimates of potential water savings from improved irrigation efficiency, for 19P u b l ic P o l ic y I n stit u te of C a l ifor n ia California Economic Policy Lawns and Water Demand in California instance. Maddaus and Mayer (2001) estimate that these rates could be even lower, within the range of 30 to 50 percent. 29 On-site systems rely on either a solar sensor or a temperature sensor, in both cases combined with a rain sensor. 30 Bamezai (2001); Hunt, et al. (2001); Municipal Water District of Orange County and Irvine Ranch Water District (2004). IRWD did not adjust the controllers after installation to simulate the minimal consumer adjustment that they expected would happen under normal circumstances. 31 Santa Barbara County Water Agency (2003). 32 Interview with Lynn Lipinski, John Wiedman, and Tim Blair, MWDSC, October 28, 2005; Kissinger and Solomon (2005). With these technologies, irrigation efficiency would jump from 50 to 69 percent. 33 For a typical home in the Coastal zone, our estimates generate slightly lower per household savings from ET controllers than the 41 gallons per day found in the Irvine Ranch Water District (Bamezai, 2001). That pilot study targeted water users in the top 20 percent of households, who likely had either larger lawns, lower irrigation efficiency, or a combination of these factors. 34 See http://www.mwdoc.com/SmarTimer/ETControllers. htm for a list of products eligible for rebates under a joint program by the Municipal Water District of Orange County and the Irvine Ranch Water District. One system listed has a starting price of $1,400, but it is mainly directed at commercial clients. The price of on-site sensor-based controllers ranges from $140 to $260 for an eight-valve system, and the price of satellite-linked systems starts in the range $560 to $650. After year two, a monthly subscription fee of $4 is charged. Installation costs range from $75 to $130 (the higher price includes rooftop installation of solar sensors). 35 Utility rebates are assumed to be $20 per valve. For the Coastal zone, we assume an average of nine valves (the current practice in Orange County); for the Inner Coastal and Central zones, an average of ten valves; and for the Desert zone, an average of 11 valves, to take into account larger lot sizes. 36 We assume a cost per controller of $40, in line with current programs in Orange County. 37 These rates are calculated for a sample of 251 utilities with uniform rates using data in Black and Veatch (2003). The “low” price ($242/acre-foot) is the average rate charged in 2003 in the San Joaquin Valley, and the “high” price ($678/acre-foot) is the comparable rate for the South Coast region. Average rates were higher in the Bay Area ($827) and the Central Coast ($711) and lower in the Inland Empire ($453) and the Sacramento Valley ($265). Marginal rates may be higher in some increasing block rate systems, which are not included in these calculations. 38 Some urban utilities have access to lower-cost sources, notably through purchases of farm water and underground storage, which can cost as little as $100 to $200 per acrefoot in some locations (Hanak, 2005). 39 For instance, Gleick et al. (2003) have argued that the non-water cost savings from more efficient irrigation practices could be substantial. 40 The Irvine studies mentioned above found that run-off was reduced by 50 percent for homes retrofitted with ET controllers (Municipal Water District of Orange County and Irvine Ranch Water District, 2004). 41 Interview with Lynn Lipinski, John Wiedmann, and Tim Blair (MWDSC), October 28, 2005. 42 Information provided by Tracy Bower, SNWA, February 2005 and Kent Sovocool, SNWA, January 2006. These estimates cover turf removal and installation of the new landscape, including a drip irrigation system. During the SNWA’s field study in the late 1990s (Sovocool, 2005), the average costs were on the order of $2 per square foot. These costs have been rising in recent years, in part because more people are using contractors to do the conversion and in part because of a loss of scale economies as people convert smaller plots. 43 Using irrigation submeters, SNWA monitored over 300 single-family homes that had converted at least 500 square feet of turf grass to “xeric” (low-water) landscapes (Sovocool, 2005). 44 This assumes, as above, that 25 percent of water needs are met by rainfall. Alternatively, the same ET adjustment factor (160%) could be attained with 50 percent irrigation efficiency and no allocation of rainfall to cover plant needs. 45 The maintenance survey was conducted by mail in the summer of 2000, drawing from a sample of participants in SNWA’s turf conversion program. Respondents were asked to record their time and capital costs (lawnmowers, fertilizers, etc.) for their residential landscapes. Usable records on costs were available for 216 cases, of which 50 had at least 60 percent turf in their gardens and 166 had at least 60 percent xeriscape landscape, with an average landscaped area of 1,750 square feet. The annual capital costs were $214 lower for the yards with more xeriscape (yielding a savings of $0.12/square foot), and these residences used 2.3 fewer hours of labor per month (yielding a savings of $0.23/square foot if valued at $14.50 per hour, a price assumed for unskilled landscaping work). See Hessling (2001) and Sovocool (2005). 46 Notably, it set a standard for irrigation efficiency of at least 62.5 percent, and it advocated a 1/3:1/3:1/3 crop mix (see Table 4). For details, see California Urban Water Conservation Council (2005). 47 For an overview of flexible, water-smart landscaping approaches, see Department of Water Resources (2002). 20 P u b l ic P o l ic y I n stit u te of C a l ifor n ia California Economic Policy Lawns and Water Demand in California References Bamezai, Anil, “ET Controller Savings Through the Second Post-Retrofit Year: A Brief Update,” Western Policy Research, April 2001, available at http://irwd.com/Conservation/ETsavings1.pdf. Bamezai, Anil, LADWP Weather-Based Irrigation Controller Pilot Study, Western Policy Research, August 2004, available at http://www.cuwcc.org/uploads/product/LADWP-IrrigationController-Pilot-Study.pdf. Bamezai, Anil, Robert Perry, and Carrie Pryor, Water Efficient Landscape Ordinance (AB 325): A Statewide Implementation Review, a report submitted to the California Urban Water Agencies, Western Policy Research, Santa Monica, California, March 2001. Baumann, Duane D., John J. Boland, and W. Michael Hanemann, Urban Water Demand Management and Planning, McGraw-Hill, New York, 1997. Black and Veatch, California Water Charge Survey, Management Consulting Division, Irvine, California, 2001. Black and Veatch, California Water Charge Survey, Management Consulting Division, Irvine, California, 2003. Bowles, Jennifer, “Inland Area’s Thirst Growing,” The Press-Enterprise, Riverside, California, July 27, 2005. California Bay Delta Authority, “Final Draft Year 4 Comprehensive Evaluation of the CALFED Water Use Efficiency Element,” Sacramento, California, December 2005. California Urban Water Agencies, Urban Water Conservation Potential, Sacramento, California, August 2001. California Urban Water Agencies, Urban Water Conservation Potential 2003 Technical Update, Sacramento, California, July 2004. California Urban Water Conservation Council (CUWCC), Water Smart Landscapes for California. AB 2717 Landscape Task Force Findings, Recommendations and Actions, report to the Governor and the Legislature, Sacramento, California, December 2005. Coachella Valley Water District, “CVWD Board Approves Water-Efficient Landscape Model Ordinance,” CVWD Press Release, March 2003, available at http://www.cvwd. org/pressrel/Landscape_Ordinance.pdf. Dalhuisen, Jasper M., Raymond J.G.M. Florax, Henri L.F. de Groot, and Peter Nijkamp, “Price and Income Elasticities of Residential Water Demand: A MetaAnalysis,” Land Economics, Vol. 79, No. 2, May 2003, pp. 292–308. Department of Finance, Population Projections by Race/ Ethnicity, Gender and Age for California and Its Counties 2000–2050, Sacramento, California, May 2004. Department of Finance, E-1 City/County Population Estimates, with Annual Percent Change, January 1, 2004 and 2005, Sacramento, California, May 2005. Department of Water Resources, Implementation of the California Water Plan, Bulletin 160-66, Sacramento, California, 1966. Department of Water Resources, Water for California: The California Water Plan, Outlook in 1970, Bulletin 160-70, Sacramento, California, 1970. Department of Water Resources, California Water Plan, Bulletin 160-74, Sacramento, California, 1974. Department of Water Resources, The California Water Plan: Projected Use and Available Water Supplies to 2010, Bulletin 160-83, Sacramento, California, 1983. Department of Water Resources, Memorandum Report Additional Information for Bulletin 160-87, Sacramento, California, 1987. Department of Water Resources, Urban Water Use in California, Bulletin 166-4, Sacramento, California, August 1994a. Department of Water Resources, California Water Plan Update, Bulletin 160-93, Sacramento, California, 1994b. Department of Water Resources, California Water Plan Update, Bulletin 160-98, Sacramento, California, November 1998. Department of Water Resources, Water-Efficient Landscapes, Office of Water Use Efficiency, 2002, available at http://www.owue.water.ca.gov/docs/water_efficient_landscapes.pdf. Department of Water Resources, Water Recycling 2030: Recommendations of California’s Recycled Water Task Force, Sacramento, California, June 2003a. Department of Water Resources, Water Desalination: Findings and Recommendations, Sacramento, California, October 2003b. Department of Water Resources, Water Use–Water Supply Balances, California Land and Water Use, Sacramento, California, April 2004, available at http://www.landwateruse. water.ca.gov. Department of Water Resources, California Water Plan Update, Bulletin 160-05, Sacramento, California, December 2005. Dzieglielewski, B., et al., Seasonal Components of Urban Water Use in Southern California, Planning and Management Consultants, Ltd., Carbondale, Illinois, 1990. Gleick, Peter H., Dana Haasz, Christine Henges-Jeck, Veena Srinivasan, Gary Wolf, Katherine Kao Cushing, 21P u b l ic P o l ic y I n stit u te of C a l ifor n ia California Economic Policy Lawns and Water Demand in California and Amardip Mann, Waste Not, Want Not: The Potential for Urban Water Conservation in California, The Pacific Institute, Oakland, California, November 2003. Hanak, Ellen, Who Should Be Allowed to Sell Water in California? Third-Party Issues and the Water Market, Public Policy Institute of California, San Francisco, California, 2003. Hanak, Ellen, Water for Growth: California’s New Frontier, Public Policy Institute of California, San Francisco, California, 2005. Hanemann, W. Michael, and Julie A. Hewitt, “A Discrete/ Continuous Choice Approach to Residential Water Demand under Block Rate Pricing,” Land Economics, Vol. 71, 1995, pp. 173–192. Hayhoe, Katharine, et al., “Emissions Pathways, Climate Change, and Impacts on California,” Proceedings of the National Academy of Sciences, Vol. 101, No. 34, August 2004, pp. 12422–12427. Hessling, Michael, “Turf Landscapes versus Xeriscapes: Analysis of Residential Landscapes in the Las Vegas Valley, Nevada,” master’s project submitted in partial fulfillment of the requirements for the Master of Environmental Management degree in the Nicholas School of the Environment of Duke University, Durham, North Carolina, 2001. Hood, Jeff, “Lodi Council Wants Water Meters in Sooner,” Stockton Record, December 7, 2005. Hunt, Theodore, Dale Lessick, et al., “Residential WeatherBased Irrigation Scheduling: Evidence from the Irvine ‘ET Controller’ Study,” Irvine Ranch Water District, June 2001, available at http://www.irwd.com/welcome/FinalETRpt.pdf. Kissinger, Joseph, and Kenneth H. Solomon, “Uniformity and Water Conservation Potential of Multi-Stream, MultiTrajectory Rotating Sprinklers for Landscape Irrigation,” June 2005, available at http://www.cuwcc.org/landscape_ task_force/SolomonKissinger.pdf. Lund, Jay, et al., Climate Warming and California’s Water Future, Report 03-1, Center for Environmental and Water Resource Engineering, University of California, Davis, California, March 2003. Maddaus, Lisa, and Peter W. Mayer, “Splash or Sprinkle? Comparing the Water Use of Swimming Pools and Irrigated Landscapes,” paper presented at the annual conference of the American Water Works Association, Washington, D.C., 2001. Mansur, Erin T., and Sheila M. Olmstead, “The Value of Scarce Water: Measuring the Inefficiency of Municipal Regulations,” AEI-Brookings Joint Center for Regulatory Studies, Working Paper 06-01, Washington, D.C., January 2006. Mayer, Peter W., William B. DeOreo, Eva M. Opitz, Jack C. Kiefer, William Y. Davis, Benedykt Dziegielewski, and John Olaf Nelson, Residential End Uses of Water, AWWA Research Foundation and American Water Works Association, Denver, Colorado, 1999. Municipal Water District of Orange County and Irvine Ranch Water District, The Residential Runoff Reduction Study, July 2004, available at http://www.irwd.com/Conservation/R3-Study-Revised11-5-04.pdf. Olmstead, Sheila M., W. Michael Hanemann, and Robert N. Stavins, “Do Consumers React to the Shape of Supply? Water Demand under Heterogeneous Price Structures,” Resources for the Future Discussion Paper 05-29, Washington, D.C., June 2005. Opitz, E. M., and R. J. Hauer (Planning and Management Consultants, Ltd), Water Conservation Baseline Study, prepared for the East Bay Municipal Utility District, Oakland, California, 1995. Santa Barbara County Water Agency, County ET Controller Distribution and Installation Program, Final Report, 2003, available at http://www.hydropoint.com/images/ pdf/SantaBarbaraYear1Report.pdf. Sovocool, Kent A., Xeriscape Conversion Study, Final Report, Southern Nevada Water Authority, 2005, available at http://www.snwa.com/assets/pdf/xeri_study_final.pdf. Water Resources Engineering, Inc., East Bay Municipal Utility District Water Conservation Market Penetration Study, final report, San Francisco, California, March 2002. 22 P u b l ic P o l ic y I n stit u te of C a l ifor n ia California Economic Policy Lawns and Water Demand in California About the Authors Ellen Hanak is a research fellow at the Public Policy Institute of California. Matthew Davis recently completed the Master of City Planning program at UC Berkeley. During the course of our research on outdoor water conservation policies, we received helpful input from numerous individuals working in water utilities and experts in water conservation technologies. We also thank Scott Matyac and Morrie Orang of the Department of Water Resources for initial guidance on the research and for making available information on evapotranspiration zones. David Haskel and Steve Ciccarella provided valuable research assistance. Dan Carney (Marin Municipal Water District), Michael Hazinski (East Bay Municipal Utilities District), John Landis (UC Berkeley), Jeff Loux (UC Davis), Scott Matyac, Marsha Prillwitz (California Urban Water Conservation Council), and Public Policy Institute of California colleagues Jon Haveman, David Neumark, and Michael Teitz provided helpful comments on a draft version of the report and Lynette Ubois and Patricia Bedrosian (RAND Corporation) provided valuable editorial assistance. Responsibility for any errors lies solely with the authors. Board of Directors Thomas C. Sutton, Chair Chairman and Chief Executive Officer Pacific Life Insurance Company Linda Griego President and Chief Executive Officer Griego Enterprises, Inc. Edward K. Hamilton Chairman Hamilton, Rabinovitz & Alschuler, Inc. Gary K. Hart Founder Institute for Education Reform California State University, Sacramento Walter B. Hewlett Director Center for Computer Assisted Research in the Humanities David W. Lyon President and Chief Executive Officer Public Policy Institute of California Cheryl White Mason Vice-President Litigation Legal Department Hospital Corporation of America Ki Suh Park Design and Managing Partner Gruen Associates Constance L. Rice Co-Director The Advancement Project Raymond L. Watson Vice Chairman of the Board Emeritus The Irvine Company Carol Whiteside President Great Valley Center The Public Policy Institute of California is a private, nonprofit research organization established in 1994 with an endowment from William R. Hewlett. The Institute conducts independent, objective, nonpartisan research on the economic, social, and political issues affecting Californians. The Institute’s goal is to raise public awareness of these issues and give elected representatives and other public officials in California a more informed basis for developing policies and programs. PPIC does not take or support positions on any ballot measure or on any local, state, or federal legislation, nor does it endorse, support, or oppose any political parties or candidates for public office. PUBLIC POLICY INSTITUTE OF CALIFORNIA 500 Washington Street, Suite 800 San Francisco, California 94111 Telephone: (415) 291-4400 Fax: (415) 291-4401 www.ppic.org ISSN #1553-8737 Recent issues of California Economic Policy Trade with Mexico and California Jobs Are Businesses Fleeing the State? Interstate Business Relocation and Employment Change in California A Decade of Living Wages: What Have We Learned? Recent Trends in Exports of California’s Information Technology Products The Workers’ Compensation Crisis in California: A Primer are available free of charge on PPIC’s website www.ppic.org Public Policy Institute of California 500 Washington Street, Suite 800 San Francisco, California 94111 In This Issue of CEP Lawns and Water Demand in California NON-PROFIT ORG. U.S. POSTAGE PAID Brisbane, CA PERMIT #83" ["post_date_gmt"]=> string(19) "2017-05-20 09:38:34" ["comment_status"]=> string(4) "open" ["ping_status"]=> string(6) "closed" ["post_password"]=> string(0) "" ["post_name"]=> string(10) "ep_706ehep" ["to_ping"]=> string(0) "" ["pinged"]=> string(0) "" ["post_modified"]=> string(19) "2017-05-20 02:38:34" ["post_modified_gmt"]=> string(19) "2017-05-20 09:38:34" ["post_content_filtered"]=> string(0) "" ["guid"]=> string(52) "http://148.62.4.17/wp-content/uploads/EP_706EHEP.pdf" ["menu_order"]=> int(0) ["post_mime_type"]=> string(15) "application/pdf" ["comment_count"]=> string(1) "0" ["filter"]=> string(3) "raw" ["status"]=> string(7) "inherit" ["attachment_authors"]=> bool(false) }