Americans Using Less Water than 35 Years Ago

The information reflects withdrawals from the nation’s rivers, streams, lakes, estuaries and aquifers for major uses.

The report, "Estimated Use of Water in the United States in 2005," shows that in 2005 Americans used 410 billion gallons per day, slightly less than in 2000.

The declines are 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 along with the population that depends on these supplies.

"The importance of this type of data to the American public cannot be exaggerated," said Assistant Secretary for Water and Science Anne Castle.

"The Department of the Interior provides the nation with the best source of information about national and regional trends in water withdrawals," she said. "This information is invaluable in ensuring future water supplies and finding new technologies and efficiencies to conserve water."

Nearly half of the 410 billion gallons per day used by Americans in 2005 was for producing electricity at thermoelectric power plants.

Irrigation accounted for 31 percent and public supply 11 percent of the total.

The remaining nine percent 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 percent of our water use in 2005, the improvements in efficiency and technology give us hope for the future," Castle said.

Water for irrigation in California's Central Valley, a fertile agricultural area (Photo by Aquafornia)

"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," Castle said.

The USGS series of five-year reports provides information valuable to states and water suppliers because the water-use estimates are broken down by state, source, and category of water use.

California is one of just four states that accounted for more than one-fourth of all fresh and saline water withdrawn in the United States in 2005, the report shows. The other three states are Texas, Idaho, and Florida.

In California, 53 percent of the total withdrawals of 45,700 million gallons per day were for irrigation, and 28 percent 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 majority of irrigation withdrawals and irrigated acres are in the Western states, but significant increases in irrigation have occurred in some Southeastern states.

The average amount of water withdrawn to produce a kilowatt-hour of electricity in the United States has decreased steadily from 1950 to 2005. The USGS report attributes this change to an increase in the number of power plants that use alternatives to once-through cooling.

The full report is available at http://pubs.usgs.gov/circ/1344. Additional water use information is available at http://water.usgs.gov/watuse/.

Copyright Environment News Service (ENS) 2009. All rights reserved.