The U.S. Geological Survey maintains national data bases of water-use information. The data are collected and compiled every five years for each State, the District of Columbia, Puerto Rico, and the U.S. Virgin Islands. County, state, and national water-use estimates may be downloaded from the National Water Information System Web (NWISWeb) interface, Water Data for the Nation, by selecting the Water Use button or data category pull-down. Data on NWISWeb represent the current best estimates, and may have been revised from previous publications. Data available from the USGS County Water-Use generally reflect the published report, and may have been revised in subsequent analyses. Note: State-level data from 1950-1980 and watershed data are not available on NWISWeb, but they can be downloaded USGS County Water-Use Data link.

The datasets in this data release contain the results of an analysis of the U.S. Geological Survey's historical water-use data from 1985 to 2015. Data were assessed to determine the top category of water use by volume. Data from groundwater, surface water, and total water (groundwater plus surface water) use were parsed by water type, and the top category of use by county or the geographic region or local government equivalent to a county (for example, parishes in Louisiana) was determined. There are two sets of results provided, one for the "Priority" categories of water use and the second for all categories of water use. "Priority" categories are irrigation, public supply, and thermoelectric power and comprise 90 percent of all water use nationwide. In addition to the priority categories, the remaining categories of water use are as follows: aquaculture, domestic, industrial, livestock, and mining. Water-use data historically have been compiled at the county level every 5 years as part of the U.S. Geological Survey's National Water Use Science Project. In 2020 the U.S. Geological Survey began transitioning the collection of water-use data from every 5 years to an annual collection, from county level to hydrologic unit code (HUC) 12, and to a model-based approach. To assist in the transition, an assessment of the current (2022) historical water-use data was done by the Water-Use Gap Analysis Project.