The total amount of water withdrawn in Illinois during 1988 was about 18,756 million gallons per day (Mgal/d). About 1,170 Mgal/d, or 37 percent, of the total water withdrawn in Illinois, excluding withdrawals for thermoelectric-power generation, was ground water; about 1,998 Mgal/d of surface water was withdrawn and used, excluding withdrawals for thermoelectric-power generation. About 25 Mgal/d of the total ground water withdrawn was saline. Seventy-five percent of the total surface water, excluding withdrawals for thermoelectric-power generation, was withdrawn by public-supply facilities. Self-supplied industrial withdrawals were the next largest use of surface water. Thirty-nine percent of the total ground water was withdrawn by public-supply facilities. Irrigation was the next largest use of ground water. Sixty-two percent of the total water withdrawn, excluding thermoelectric withdrawals, in Illinois during 1988 was for public-supply facilities. Self-supplied withdrawals by industries and for irrigation were the next largest uses of water in Illinois during 1988.
The total water withdrawn for thermoelectric-power generation was about 15,589 Mgal/d. Water withdrawn and delivered from public-supply facilities in Illinois during 1988 totaled about 1,956 Mgal/d. Surface water and ground water were the sources for about 1,495 and 462 Mgal/d, respectively, of the withdrawals for public supply. The total water obtained from Lake Michigan for public-water supply was about 1,214 Mgal/d. About 122 Mgal/d was withdrawn for self-supplied domestic purposes. Total self-supplied withdrawals and deliveries from public-water facilities for commercial use were about 654 Mgal/d. About 159 Mgal/d was self-supplied by the commercial establishments. Total irrigation water withdrawals were about 302 Mgal/d. Although irrigated acreage in Illinois has increased from 265,036 acres in 1986 to 281,370 acres in 1988, the most significant factor for the increased irrigation water use was the drought conditions throughout the entire State. Total estimated livestock withdrawals were about 56 Mgal/d. Total self-supplied withdrawals and deliveries from public-supply facilities for industrial purposes were about 743 Mgal/d. About 480 Mgal/d was self-supplied withdrawals by industrial facilities. A total of about 94 Mgal/d was withdrawn during mining activities. A total of about 34 Mgal/d was withdrawn during mining from ground-water sources; about 25 Mgal/d of the ground water withdrawn was saline.