In 1990, the U.S. Geological Survey (USGS) completed a study of the hydrogeology of Huron County, Michigan (Sweat, 1991). In 1993, Huron County and the USGS entered into an agreement to continue collecting water levels at selected wells throughout Huron County. As part of the agreement, the USGS has provided training and instrumentation for County personnel to measure, on a quarterly basis, the depth to water below the land surface in selected wells. The agreement includes the operation of continuous water-level recorders installed on four wells in Bingham, Fairhaven, Grant and Lake Townships (fig. 1). County personnel make quarterly water-level measurements of 22 other wells. Once each year, County personnel are accompanied by USGS personnel who provide a quality assurance/quality control check of all measurements being made.