The US Geological Survey report, Estimated Use of Water in the United States in 2005, By Joan F. Kenny, et al, released in 2009, compares recent and historical findings on water withdrawls for fresh surface water, groundwater, irrigation, thermo-electric power generation, public supply, self-supplied industrial use, and livestock, among others.
The Blog EarthSky spoke to Robert Hirsch of the USGA, and explained that the agency had “compared the new report’s findings with past data, and discovered that Americans have done more with less water since 1975. Water use, per person, is down about 30 percent. Hirsch said this can be attributed, in part, to advances in agriculture and energy. That’s because most of the water an average American uses – up to 80 percent – goes into producing food and electricity.”
For example, the USGS study found that, “About 67 percent of fresh groundwater withdrawals in 2005 were for irrigation, and 18 percent were for public supply. More than half of fresh groundwater withdrawals in the United States in 2005 occurred in six States.
Withdrawals for irrigation in 2005 were 128 Bgal/d, about 8 percent less than in 2000 and approximately equal to estimates of irrigation water use in 1970.”
In addition to general conclusions and detailed discussion of each sector, county level data is available for every state in the US.