The bedrock aquifers in the Colorado Plateau of Utah supply water that ranges widely in chemical quality and yield. The range of dissolved solids in 649 samples collected from 534 wells, springs, and water-yielding mine tunnels was from less than 100 to more than 390.000 ppm (parts per million). The yield of wells ranged from less than 1 to 54,000 barrels of water per day (less than 1 to 1,600 gallons per minute); whereas the yield of springs ranged from less than 1 to 4,100,000 barrels of water per day (less than 1 to 121,000 gallons per minute).