This case study reviews the hydrologic cycle and uses a water balance equation to examine the hydrology of White Bear Lake, a 2,531-acre natural water body near St. Paul, Minnesota. Since 2004, lake water levels have fallen five feet below their ordinary high-water mark, resulting in broad areas of exposed lakebed. In 2012, a group of area residents filed a joint lawsuit against the Minnesota Department of Natural Resources (DNR), claiming mismanagement of the region's groundwater resources by allowing too many permits to be issued for groundwater extraction. The suit alleges that neighboring cities pumped increasing amounts of groundwater out of the underlying Prairie du Chien and Jordan aquifers, which are known to supply groundwater to the lake. The central activity of the case involves students using a supplied spreadsheet (Supplemental Materials) to model the roles of various water pathways on the surface water levels in White Bear Lake. The case was written for either an undergraduate hydrology or hydrogeology course, although the assignment could be modified for graduate students.