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 semiannually by the U.S. Geological Survey. Maps are prepared showing 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-field areas that supplied 155 million gallons to municipalities on May 12, 1980. The water is withdrawn from the Floridan aquifer, the major aquifer in Florida. The effect of localized withdrawal of ground water is shown on the maps as depressions in both the potentiometric and water-table surfaces. Water levels were lower in May 1980 than in September 1979 and a little higher than the average May levels. Change of water levels ranged from a decrease of 12 feet at Verna well field to an increase of 7 feet at Eldridge-Wilde well field. (USGS)