The Duck River in Tennessee supplied about 18.9 Mgal of water/d to Tullahoma, Manchester, Lewisburg, Columbia, and other cities. Municipal water use increased to 20.9 Mgal/d in 1990; projections indicate increases in demand for the next 25 yr. Socioeconomic and water use data from the basin for 1989 were used to calibrate the water use models within the Institute for Water Resources Municipal and Industrial Needs (IWR-MAIN) System. The models were used to estimate future water use demand in the basin for the years 1995, 2000, and 2015. Projections showed demands of about 24.3 Mgal/d in 1995; 28.3 Mgal/d in 2000; and 39.0 Mgal/d in 2015. Increases in withdrawals from the Duck River downstream from Shelbyville could reduce the minimum flow at Columbia from 119 to 83.8 cu feet/s. The study also included an overview of the potential for developing groundwater resources in the area. Statistical analyses of yields to 5,938 wells showed that the highest yields are in Coffee County, but 75 percent of the wells in Coffee County produced less than 30 gal/m. However, measurements of streamflow losses along tributaries to the Duck River suggest that the potential for development of groundwater does exist at specific sites.