Spencer County had an estimated population of 10,049 in 1999 with 90 percent on public water. The estimated 2008 population was 18,461 with 97 percent served by a water utility.In areas not served by public water, about 20 percent of the households use private domestic wells and the majority use other sources.
The Water Resource Development Commission has prepared a report on water-supply infrastructure in the county.
It is estimated that there are over 200,000 water wells in Kentucky. The Kentucky Groundwater Data Repository, maintained by the Kentucky Geological Survey, has information on over 50,000 of these wells. The locations of wells and springs in the county for which data are available is shown on the map of wells and springs in the county. Certified well drillers in Kentucky.