Water use in the U.S. has dropped to its lowest since before 1970, according to a report published by the U.S. Geological Survey (USGS). The report, Estimated use of water in the United States in 2010, is the 13th in a series of USGS Circular reports that have been published every five years since 1950.
The 60-year span of national reports represents the longest compilation record of water-use data by a federal agency in the U.S. Estimates of withdrawals enable the depiction of trends in total water use for the nation among different geographic areas, categories of use, and sources over time.
Water use in the U.S. in 2010 was estimated to be about 355 billion gallons per day (Bgal/d), which was 13 percent less than in 2005. The 2010 estimates put total withdrawals at the lowest level since before 1970. Freshwater withdrawals were 306 Bgal/d, or 86 percent of total withdrawals, and saline-water withdrawals were 48.3 Bgal/d, or 14 percent of total withdrawals, according to the report.
Total water withdrawals were estimated for eight categories of use: public supply, domestic, irrigation, livestock, aquaculture, industrial, mining, and thermoelectric power. The three largest categories were thermoelectric power, irrigation, and public supply, cumulatively accounting for 90 percent of the national total. The remaining categories of industrial, aquaculture, mining, domestic, and livestock together were just about 10 percent of total water withdrawals estimated in this report.
In 2010, more than 50 percent of the total withdrawals were accounted for by 12 States. California accounted for about 11 percent of the total withdrawals and 10 percent of freshwater withdrawals in the United States, predominantly for irrigation. Texas accounted for about 7 percent of total withdrawals, predominantly for thermoelectric power, irrigation, and public supply. Florida accounted for 18 percent of the total saline-water withdrawals in the United States, mostly from surface-water sources for thermoelectric power. Oklahoma and Texas accounted for about 70 percent of the total saline groundwater withdrawals in the U.S., mostly for mining.
For the first time, withdrawals for public water supply declined between 2005 and 2010, despite a 4 percent increase in the nation’s total population. The number of people served by public-supply systems continued to increase and the public-supply per capita use declined to 89 gallons per day in 2010 from 100 gallons per day in 2005.
Declines in industrial withdrawals can be attributed to factors such as greater efficiencies in industrial processes, more emphasis on water reuse and recycling, and the 2008 U.S. recession, resulting in lower industrial production in major water-using industries.