Central to my “decoupling” argument is the premise that, in addition to the water conservation we’ve already seen, we have significant opportunities to conserve yet more. This from  Dave Cogdill (California Building Industry Association and an adviser to the Public Policy Institute of California) puts some numbers to the thing:

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.