Oct 30, 2009

Report: United States Using Less Water Than 35 Years Ago

Declines attributed to increased use of efficient irrigation systems, alternative technologies

The United States is using less water than during the peak years of 1975 and 1980, according to water use estimates for 2005. Despite a 30% population increase during the past 25 years, overall water use has remained fairly stable, according to a new U.S. Geological Survey report.

Assistant Secretary of the Interior Anne Castle announced the report, “Estimated Use of Water in the United States in 2005,” as part of her keynote speech at the Atlantic Water Summit in the National Press Club.

The report shows that, in 2005, Americans used 410 billion gallons per day, slightly less than in 2000. The declines were attributed to the increased use of more efficient irrigation systems and alternative technologies at power plants. Water withdrawals for public supply have increased steadily since 1950--when USGS began the series of five-year trend reports--along with the population that depends on these supplies.

“The importance of this type of data to the American public cannot be exaggerated,” Castle said. “The Department of the Interior provides the nation with the best source of information about national and regional trends in water withdrawals. This information is invaluable in ensuring future water supplies and finding new technologies and efficiencies to conserve water.”

Almost half (49%) of the 410 billion gallons per day used by Americans was for producing electricity at thermoelectric power plants. Irrigation accounted for 31% and public supply 11% of the total. The remaining 9% of the water was for self-supplied industrial, livestock, aquaculture, mining and rural domestic uses.

“Because electricity generation and irrigation together accounted for a massive 80% of our water use in 2005, the improvements in efficiency and technology give us hope for the future,” Castle said. “The report also underscores the importance of recognizing the limits of the drinking water supplies on which our growing population depends. While public supply withdrawals have continued to increase overall, per capita use has decreased in many states during recent decades.”

The water use estimates are broken down by state, source and category of water use. California, for example, is one of four states--joining Texas, Idaho and Florida--that accounted for more than one-fourth of all fresh and saline water withdrawn in the United States in 2005. More than half (53%) of the total withdrawals in California were for irrigation, and 28% were for thermoelectric power.

The largest uses of fresh surface water were power generation and irrigation, and the states with the largest fresh surface water uses were California, Texas, Idaho and Illinois. The largest use of fresh groundwater was irrigation, and the states with the largest fresh groundwater uses were California, Texas, Nebraska and Arkansas.

The full report is available at http://pubs.usgs.gov/circ/1344.