SAN FRANCISCO, California, July 12, 2006 — Over the next 25 years, Californians’ historic love affair with lawns will be a major factor in escalating water demand in the state’s cities and suburbs, according to a report released today by the Public Policy Institute of California (PPIC). The demand will be aggravated by the dominant land-use pattern in inland areas: single-family homes with lush lawns. Without efforts aimed specifically at reducing outdoor urban water use, the demand will pose significant financial and environmental challenges for California.
According to the study, single-family homes typically use twice as much water as multifamily units. In the interior parts of the state, the share of single-family homes in new housing has risen from 80 percent to 86 percent since 2000. Conversely, the coast has seen a surge in multifamily housing, with the share of new townhomes, condominiums, and other multifamily units rising from 37 percent to 46 percent.
What difference do these divergent trends make for water demand? Analysis of detailed housing data indicates that to maintain a nice lawn, a typical inland residence needs two to three times more water than a coastal residence. As a result, in inland areas, landscaping typically accounts for over half of all residential water use—versus roughly a third in coastal regions. Although land use is the primary factor in these differences, inland water demand is compounded by the significantly hotter, dryer inland climates. It will be driven even higher by population growth: At least half of the 11 million additional residents California expects by 2025 will live in interior regions.
“Do the math,” says PPIC economist Ellen Hanak, who co-authored the study with Matthew Davis, a recent graduate of UC Berkeley. “We’re facing the prospect of many more people, with more lawns and gardens, in the state’s hottest, driest regions – that adds up to a lot of water.”
Landscaping choices also matter. “Californians have long planted vegetation that would grow naturally in more humid climates,” says Hanak. For example, the state’s most common lawn type is a cool-season turf grass requiring several times more water than native plants. The report, Lawns and Water Demand in California, finds that recent conservation efforts, such as improved irrigation technologies and programs that replace some lawns with less-thirsty plants, have significant water-saving potential.
The Public Policy Institute of California is a private, nonprofit organization dedicated to improving public policy in California through objective, nonpartisan research on major economic, social, and political issues. The institute was established in 1994 with an endowment from William R. Hewlett.