This paper presents the methods used in studying the groundwater hydrology of an area in Harvey and Sedgwick Counties, Kansas, from which the city of Wichita derives its water supply. A summary of the data available for study is presented and several hydrologic factors are evaluated. The relationship between groundwater levels and precipitation is shown, and recharge is estimated. The effect of pumping on water levels is shown graphically, and the quantity of water withdrawn from storage is estimated from several water-table contour maps. The data are analyzed and the quantity of water available for pumping is estimated.