In 2005, the United States estimated total water withdrawals at 410 billion gallons per day (Bgal/d), with 349 Bgal/d being freshwater and 61 Bgal/d saline. Freshwater withdrawals were 85% of total withdrawals, with 79.6 Bgal/d from groundwater and 270 Bgal/d from surface water. Thermoelectric power accounted for 41% of all freshwater withdrawals, with 201 Bgal/d withdrawn, and irrigation accounted for 37% of all freshwater withdrawals, with 128 Bgal/d withdrawn. Public supply accounted for 13% of all freshwater withdrawals, with 44.2 Bgal/d withdrawn, and domestic use accounted for 58% of total public supply use. Irrigation withdrawals increased from 1970 to 2005, with 128 Bgal/d withdrawn in 2005. Irrigated acreage increased from 25 million acres in 1950 to 58 million acres in 1980, then remained fairly constant before increasing in 2000 and 2005 to more than 60 million acres. The number of acres irrigated using sprinkler and microirrigation systems increased and accounted for 56% of total irrigated acreage in 2005. Thermoelectric power withdrawals stabilized or decreased since 1980, while public supply and domestic use withdrawals increased since estimates began. Fresh surface water was the source for most withdrawals, with 30% of all fresh surface-water withdrawals occurring in five states. Fresh groundwater was the source for 67% of all withdrawals, with 52% in Florida for public supply and 34% for irrigation. The report provides water-use estimates by source and by state for eight categories of water use, including public supply, domestic, irrigation, livestock, aquaculture, industrial, mining, and thermoelectric power. The report also includes trends in water use from 1950 to 2005, with changes in water use due to factors such as demographics, economic trends, legal decisions, and climatic fluctuations. The report highlights the importance of water-use information in understanding future water demands while maintaining adequate water quality and quantities for human and ecosystem needs.In 2005, the United States estimated total water withdrawals at 410 billion gallons per day (Bgal/d), with 349 Bgal/d being freshwater and 61 Bgal/d saline. Freshwater withdrawals were 85% of total withdrawals, with 79.6 Bgal/d from groundwater and 270 Bgal/d from surface water. Thermoelectric power accounted for 41% of all freshwater withdrawals, with 201 Bgal/d withdrawn, and irrigation accounted for 37% of all freshwater withdrawals, with 128 Bgal/d withdrawn. Public supply accounted for 13% of all freshwater withdrawals, with 44.2 Bgal/d withdrawn, and domestic use accounted for 58% of total public supply use. Irrigation withdrawals increased from 1970 to 2005, with 128 Bgal/d withdrawn in 2005. Irrigated acreage increased from 25 million acres in 1950 to 58 million acres in 1980, then remained fairly constant before increasing in 2000 and 2005 to more than 60 million acres. The number of acres irrigated using sprinkler and microirrigation systems increased and accounted for 56% of total irrigated acreage in 2005. Thermoelectric power withdrawals stabilized or decreased since 1980, while public supply and domestic use withdrawals increased since estimates began. Fresh surface water was the source for most withdrawals, with 30% of all fresh surface-water withdrawals occurring in five states. Fresh groundwater was the source for 67% of all withdrawals, with 52% in Florida for public supply and 34% for irrigation. The report provides water-use estimates by source and by state for eight categories of water use, including public supply, domestic, irrigation, livestock, aquaculture, industrial, mining, and thermoelectric power. The report also includes trends in water use from 1950 to 2005, with changes in water use due to factors such as demographics, economic trends, legal decisions, and climatic fluctuations. The report highlights the importance of water-use information in understanding future water demands while maintaining adequate water quality and quantities for human and ecosystem needs.