This is one of a series of maps that describes the geology and related natural resources of the Alton-Kolob coal-fields area, Utah. The purpose of this map is to show regional variations in ground-water quality as depicted by its dissolved-solids concentration. The map is based on chemical analyses of water samples from springs, streams during base flow, and wells less than 1.000 feet deep. There are significant areal and vertical variations in the ground-water quality – especially in those areas where the dissolved-solids concentrations range from 100 to 1,000 and from 500 to 3,000 mg/L (milligrams per liter). Consequently, determination of the actual chemical quality of the ground-water, including concentrations of specific ions in any given locality, can be made only by special investigation.