The most significant opportunity to reduce use of potable water for nonpotable purposes in the urban sector is landscape irrigation: 44% of all urban water is used outdoors, primarily for landscape irrigation.  Most of the water used for landscape irrigation is drinking water. 
On April 1, 2015, Governor Brown issued an Executive Order directing, among other things, mandatory statewide water use reductions. The stipulated goal was to reduce urban water use by 25 percent, an estimated savings of 1.5 million acre-feet.  The order included a directive to replace 50 million square feet of lawns statewide with drought tolerant landscaping in partnership with local governments. To implement the Governor’s directive, DWR established a turf replacement rebate program that provided $24 million in grant funds to help single family residences replace their lawns. Incentives were paid in the amount of $2 per square foot with the goal of achieving 20% of the Governor’s goal (10 million square feet).
Many of the larger water agencies offered their own rebates, some with assistance from the U.S. Bureau of Reclamation’s WaterSmart grant program.
The emphasis on turf replacements was a simple choice: in its 2013 Water Plan Update, DWR estimated that 34% of all residential water use is poured onto lawns and gardens every year. Another 10% is used for large landscapes by commercial and industrial customers, bringing the total amount of water used for urban landscapes to 44% (this estimate was down from the 50% estimated in the 2009 Water Plan). At an estimated annual urban water demand of 8 million acre-feet, 3.52 million acre-feet – 1.15 trillion gallons per year – is poured onto lawns and gardens every year, and most of that water is drinking water. Through a combination of climate-appropriate (drought tolerant) plantings and water-efficient irrigation, savings of up to 50% of water used for urban landscape irrigation have been documented by some customers that took advantage of the turf incentives. Half of the amount of water used for urban irrigation is approximately 1.76 million acre-feet – 88% of the targeted 25% urban water use reduction targeted by the Governor’s Executive Order B-29-15.
To assure that California continues diligence about saving water outdoors, the California Water Commission approved a revised Model Water Efficient Landscape Ordinance (MWELO) on July 15, 2015. Local agencies (cities and counties) are responsible for either adopting the State’s MWELO or adopting their own ordinance that must adhere to certain MWELO principles. Of particular note is the provision for a “maximum applied water allowance” (MAWA) that reduced the percentage of landscape area that can be planted with high water use plants (including turf) from 33% to 25%. Local agencies are responsible for annual compliance reporting to DWR.
 “Urban Water Use Efficiency.” Department of Water Resources. https://water.ca.gov/Programs/Water-Use-And-Efficiency/Urban-Water-Use-Efficiency.
 Governor Brown. Executive Order B-29-2015. April 1, 2015.
 California Water Commission. The 2015 Updated Model Water Efficient Landscape Ordinance, Guidance for Local Agencies. June 19, 2015.