California Code, Water Code - WAT § 10015

(a) The state's growth requires policymakers to seek creative ways to maximize the use of water resources and employ technology to conserve water whenever possible.

(b) The state's agricultural industry, as well as residential landscapers, pest control managers, park and golf course operators, water agencies, and large urban irrigators rely on the California Irrigation Management Information System (CIMIS) to provide evapotranspiration data that allows them to develop weather-based, water budgeting methods of irrigation.  A recent study found that the California Irrigation Management Information System generates $64.7 million in annual benefits to the state, at an annual cost of only eight hundred fifty thousand dollars ($850,000).

(c) Completing the development of standard data protocol for evapotranspiration data and enhancing statewide coverage of CIMIS data will allow significant improvements in landscape management and irrigation scheduling, thereby saving significant amounts of water.  Studies have shown a savings of 37 gallons per day for residential irrigation, and 545 gallons per day for nonresidential irrigation, as well as runoff reduction of up to 50 percent when weather-based irrigation controllers using evapotranspiration data are installed.

(d) The expansion of the California Irrigation Management Information System, and the use of evapotranspiration data in irrigation has other environmental benefits as well.  The reduction in urban runoff that results can lead to improved water quality, and for every one acre foot of water saved, there is a corresponding reduction of one ton of air emissions, according to the California Irrigation Management Information System Urban Resource Book (May 2000).