This is the sixth in a series of reports by the U.S. Geological Survey in cooperation with the Utah Department of Natural Resources, Division of Water Rights, which describe the water resources of selected basins in western Utah. Areas covered by previously published reports in this series are shown in figure 1 and are listed on page 29. The purpose of this report is to present available hydrologic data on the Sink Valley (Puddle Valley) area, to provide an evaluation of the potential for water-resource development in the area, and to serve as a basis for planning possible later detailed investigations.