Water use for 2005 for each county in Georgia was estimated using data obtained from various Federal and State agencies and local sources. Total consumptive water use also was estimated for each county in Georgia for 2005. Estimates of offstream water use include the categories of public supply, domestic, commercial, industrial, mining, irrigation, livestock, and thermoelectric power. The only category of instream use estimated was hydroelectric-power generation.

Total offstream water use from ground- and surface-water sources was about 5,471 million gallons per day (Mgal/d) in 2005. Surface water used in the process of thermoelectric-power generation was the largest volume of water withdrawn with withdrawals of 2,717 Mgal/d in 2005. Estimated instream water use for hydroelectric-power generation was 54,096 Mgal/d. Withdrawals for irrigation totaled 752 Mgal/d with 65 percent supplied by ground-water sources. Surface water provided 78 percent of the 1,180 Mgal/d withdrawn for public supply. Many counties in the northern Piedmont physiographic province of Georgia, an area of dense population, had a large percentage of withdrawals from surface-water sources. In contrast, in the southern Coastal Plain physiographic province part of the State, many counties had more withdrawals from ground-water sources.

As part of the Georgia Water-Use Program, statewide water-use estimates have been compiled every 5 years since 1980. During this period, water use was greatest in 1980 at 6,725 Mgal/d. Water use decreased by 31 percent to 5,353 Mgal/d in 1990 then increased to 6,487 Mgal/d in 2000. By 2005, water withdrawals had decreased to an estimated 5,471 Mgal/d primarily because of a decline in withdrawals for thermoelectric-power generation and a decline in demands as 2005 was a normal year for precipitation compared to 2000, which was in drought. Throughout the period 1980–2005, water withdrawn for thermoelectric-power generation made up the largest volume of offstream water use in Georgia. Total withdrawals for thermoelectric-power generation decreased about 24 percent in 2005 compared to 2000, due to the decommissioning of three power plants in the State. In addition, several plants operated by Georgia Power Company were retooled during this period to increase water conservation. Public-supply use steadily increased from 1980 to 2000, concurrent with increasing population in the State; however, in 2005, there was a slight decrease in public-supply use. Conversely, industrial water use decreased during the period 1980–2005. Water withdrawals for irrigation during 1980–2005 followed changing hydrologic conditions, increasing during drier years (1980 and 2000) and decreasing during normal or wetter years. Withdrawals for the categories of domestic and commercial use remained about the same during 1980–2005. Livestock and mining use increased in 2005 compared to the 2000 estimates because of changes in estimation techniques.

Consumptive water use was determined for each category of use and compiled for each county. Estimation techniques vary for each water-use category. While consumptive use varied for each county in 2005, from about 1 percent to nearly 100 percent of total withdrawals, consumptive-use estimates for the entire State totaled 1,310 Mgal/d, about 24 percent of total withdrawals.