In 1993 the U.S. Geological Survey, in cooperation with the Tennessee Department of Environment and Conservation (TDEC), began an investigation of the quality of ground water in the Beaver Creek watershed in West Tennessee. A total of 408 water samples were collected from 91 wells during 5 sampling periods in 1994. Water samples were analyzed for selected water-quality properties, fecal coliform and streptococci bacteria, nutrients, and major inorganic constituents. Selected well- construction data and information on potential sources of contamination were also collected for the 91 wells sampled. Nitrate concentrations (measured as NO<smaller>3</smaller>) ranged from a detection limit of 0.1 to 91 milligrams per liter (mg/L). Nitrate concentrations exceeding 13 mg/L were detected in 71 of the samples collected. Nitrate concentrations in water samples collected from three wells exceeded the TDEC primary drinking water standard of 44 mg/L for nitrate (measured as NO<smaller>3</smaller>). Nitrite (measured as NO<smaller>2</smaller>), ammonium (measured as NH<smaller>4</smaller>), and orthophosphate (measured as PO<smaller>4</smaller>) concentrations in samples were generally less than 0.1 mg/L (detection limit). Fecal coliform bacteria were detected in 33 of the 408 water samples collected. Samples from 21 of the 91 wells contained fecal coliform bacteria during one or more of the five sampling periods. Fecal streptococci bacteria were detected in 123 of the 408 samples. Samples from 59 wells contained fecal streptococci bacteria during one or more of the five sampling periods.