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Sources of California Water Use Data and Methods of Analysis

The USGS California Water Science Center publishes water information on many topics, including water use. USGS national guidelines for preparing 2010 water-use estimates were followed. Water-use estimates and ancillary data were entered into a State aggregate water-use database and reviewed within the USGS and by cooperating agencies.

The following national data are available to each State: U.S. Environmental Protection Agency (USEPA) Safe Drinking Water Information System (SDWIS); U.S. Census Bureau, population; U.S. Department of Agriculture (USDA) Farm and Ranch Irrigation Survey; USDA Census of Agriculture; USDA, national agricultural statistics; and U.S. Department of Energy-Energy Information Administration (USDOE-EIA), steam-electric plant statistics.

The USGS California Water Science Center is responsible for determining the most reliable sources of data, compiling and analyzing those data, determining its comprehensiveness, and estimating missing data where appropriate, and preparing documentation of the sources and methods used to estimate water use for California. California and other states have published reports on water use as part of the National Water Use Information Program.

California Water Use Data Sources

Public Supply and Domestic Supply Data

California Department of Water Resources (CDWR)

  • 2010 Public Water Systems Statistics (PWSS)
  • 2010 Urban Water Management Plan (UWMPs)

California Department of Public Health

  • Public Water System 2010 Annual Reports
  • Safe Drinking Water Information System (SDWIS) / Drinking Water Watch

Industrial, Livestock, Aquaculture, Mining, and Thermoelectric Data


Irrigation Data

USDA, National Agricultural Statistics Service (NASS)

Food and Agriculture Organization of the United Nations (FAO)

Golf Course Superintendents Association of America

Water Recycling Funding Program, California State Water Resources Control Board (WRFP)

Cooperative Extension of the University of California Division of Agriculture and Natural Resources


Precipitation Data

National Climatic Data Center, National Oceanic and Atmospheric Administration

USGS reports on national and state water-use estimates between 1950-2010 are posted on the web at:

State and county data for 1985-2010 are available at: