Let’s look at development in arid regions of the state. We really hate to quote the Public Policy Institute of California, creator of the Apocalypse vision of the Delta. But in a 2005 report, “Lawns and Water Demand in California,” the PPIC estimated that the amount of irrigated landscaping in California equaled the size of Westlands Water District.
According to our own researcher, Deirdre Des Jardins, “The report says that California’s Landscape Task Force concluded that outdoor use constitutes about half of residential demand in the state (California Urban Water Conservation Council, 2005), which was about 5.8 MAF in 2005, according to the 2005 California Water Plan.
“That would mean that residential landscaping uses as much as 2.9 MAF of water – almost three times what Westlands uses. . . . Furthermore, the water use for residential landscaping in desert areas is much higher, per capita. The PPIC report says,
“’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. 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).’
“This is because not only do lawns in inland areas use a lot more water than in coastal areas due to higher evapotranspiration — the lots are generally LARGER than coastal areas. That’s why water use in Bakersfield is about 300 gallons per day per person, twice the use of 150 gpd per person in the East Bay area.”
Deirdre uses California Water Plan figures to estimate that landscaping is 40.4% of urban water use in California. She says, “So if urban users simply cut their landscaping use by 40%, they could reduce their use of water by AT LEAST 16% statewide.” (That’s 40 percent of 40%.)
Metropolitan Water District, which gets 30% of its water from the Delta, could manage with about half of that by implementing some of the same water-saving techniques that agriculture has been using for decades – smart irrigation scheduling, and moving to drip systems. But we cannot expect MWD to use any water it saves to serve a larger number of customers, because MWD is only relevant if it is moving water.