PPIC Logo Independent, objective, nonpartisan research
Blog Post · September 29, 2016

Making Homes More Water Efficient

Outside water use varies dramatically in California depending on location—hot, dry places use more than cool, coastal cities, for example. But the state also has huge variation for inside water use. We talked to Dave Cogdill—CEO and president of the California Building Industry Association and a member of the PPIC Water Policy Center Advisory Council—who explains how California could save billions of gallons a year if older homes were as water efficient as newer ones.

PPIC: How water efficient is the state’s current housing stock?

Dave Cogdill: New homes are quite water efficient, but about two-thirds of the state’s homes were built prior to water-efficiency standards. Our studies show that homes built after 1980 are two times more efficient in water use than those built prior to these standards—mostly due to water-efficient fixtures that are required for new construction. We could save 300 billion gallons annually—enough to supply 2.5 to 3 million homes—if the state’s existing homes had to comply with these standards. We estimate it would cost $1,500 per home to convert older homes with water-saving plumbing fixtures such as toilets, showerheads, and faucets.

PPIC: What policy changes would help ensure California’s inside-home water use continues to be as efficient as possible for the long term?

DC: Finding ways to get people to retrofit is the big challenge. Better incentives would help. The drought-relief legislation passed in recent years included some money for these sorts of things, but nowhere near enough. We have to get more creative with incentive programs. It’s the old carrot-and-stick argument. Building standards for new homes are easier than addressing the problems with existing housing. The state has started to address issues with existing homes by requiring point-of-sale improvements for earthquake retrofits and pest inspections; maybe something like that would make sense for water-saving plumbing fixtures too. It wouldn’t add a lot to the cost of a house—and maybe the state could make it a deductible item.

PPIC: What steps can home builders take to increase water efficiency in housing?

DC: Inside the home we’re pretty much there—new homes save as much water as possible without requiring people to change their standard of living. While there’s not a lot more we can do inside the home, outside water use is a different story. The state’s model landscape ordinance was substantially revised this year to help respond to the drought. Our members have been very involved to make it as workable as possible. Massive savings are possible in outside water use, and in new developments we’ll be seeing a lot more hardscaping, drought-tolerant plants, less lawn, more efficient irrigation. There’s also an evolution toward using more recycled water and graywater in homes. By July 2018 homebuilders will be required to install “purple pipe” for recycled water to be used in landscape irrigation in those areas of California served by water recycling plants. In addition, the state has already taken steps to allow for on-site water recycling technologies. These more expensive “on-site” systems can add anywhere from $3,000 to $15,000 to the cost of a home, but they bring a substantial savings in water. Just to give you an idea of what’s possible, one on-site water recycling system we’re familiar with in El Dorado Hills recycles approximately 65 percent of the water used indoors. Given the price of water in many communities, these systems will pay for themselves over time.

Learn more

Read California’s Water: Water for Cities (from California’s Water briefing kit, April 2015)
Read “Water and Growth in the West” (PPIC Blog, February 18, 2016)
Visit the PPIC Water Policy Center’s water supply resource page


Paying for Water Water Supply Water, Land & Air