Estimated Use of Water in the United States
The U.S. Geological Survey (USGS), National Water Information System (NWIS) is responsible for compiling and disseminating the nation's water-use data. The USGS works in cooperation with local, state, and federal environmental agencies to collect water-use information. USGS compiles these data to produce water-use information aggregated by county, state, and national levels. Every five years, data at the county level are compiled into a national water-use data system and state-level data are published in a national circular.
Water use and conservation and related web pages. Accessed August 28, 2010.