Chemical quality of ground water, spring water, and surface water differs substantially among the three physiographic provinces. Maps showing regional variations for 18 water properties and constituents are included in this Regional Aquifer System Analysis study report. Systematic variations in water quality are due to differences in geologic and hydrologic factors that include the dominant lithology, the availability of soluble minerals, and the degree of exposure of water to rock. Most ground water in the study area is low in concentrations of dissolved minerals, is moderately hard, and is slightly acidic. Spring water is generally harder than ground water and is slightly alkaline; whereas, surface water is softer than the ground water and is also slightly alkaline.