The water table in the surficial aquifer and the potentiometric surface of the Floridan aquifer in a 1,200-square-mile area in west-central Florida are mapped semi-annually by the U.S. Geological Survey. Maps are based on water levels measured in wells each May to coincide with seasonal low levels and each September to coincide with seasonal high levels. The mapped area shows 14 well fields that supplied 200.7 million gallons to municipalities on May 18, 1981. The water is withdrawn from the Floridan aquifer, the major aquifer in Florida. The effect of localized withdrawal on ground water is shown on the maps as depressions in both the potentiometric and water-table surfaces. Water levels were lower in May 1981 than in May and September 1980. Annual change of water levels ranged from decreases of 19 feet at Sun City well field to less than 1 foot at Eldridge-Wilde well field. (USGS)