This week, California Governor Jerry Brown issued an executive order seeking a mandatory 25% reduction in water use and a requirement that new homes feature water-efficient irrigation if the builder plans to use potable water for landscaping. (The alternative, of course, is a grey-water irrigation system.) He also called for 50 million square feet of lawns to be replaced with drought-tolerant landscaping.

The restrictions come after the the California Water Resources Control Board in March prohibited residents from watering lawns within 48 hours after a rain storm and limited watering to just two days a week.

Mark Knorringa, chief executive officer of the Building Industry Association of Southern California, isn't worried for the states builders, most of whom are already building to strict state codes that limit water use. The bigger impact will be on the 7.5 million residences built before codes enacted after the 1970s drought, said Knorringa. Those often have bigger yards and lack water-saving plumbing fixtures.   Read more.