The effects of spray irrigation using municipal wastewater effluent on a ground-water system (in particular, on the water of the Floridan aquifer) were investigated. The area irrigated was 4 miles southwest of Tallahassee, Florida, on an area covered in part by pine forest and in part by selected grasses and forage crops. Hydrologic and geologic data were collected from 1972 to 1981. Hydrologic data include ground-water levels, water quality, and spray-irrigation rates. Ground-water level measurements were made at 60 wells. Water-quality samples were collected at 1 municipal wastewater effluent site, 3 springs, 17 soil sites, and 64 wells. Water-quality data were obtained from physical, chemical, and bacteriological analyses. Geologic data include geophysical logs and lithologic descriptions of 34 wells. (USGS)