Municipal water authorities are required to measure the groundwater level in several locations for a number of reasons. This is to monitor the water table, water in streams and lakes, and potential deterioration of water quality. The locations can range anywhere from wells, streams, dams and aquifers. In one instance, a municipal water authority had to measure the groundwater from several aquifers. In this case, the sample well consisted of a 4-inch well casing that was approximately 100 feet deep and periodic measurements were taken by a visiting technician monthly.