This project assembled and updated a Well Identification Table (WIT) for Iowa's Municipal Water Supply Inventory (MWSI). The MWSI combines municipal well and water supply data from the Environmental Protection Division of DNR with geological and aquifer data from the Iowa Geological Survey and raw water quality data obtained from the University Hygienic Laboratory and the US Geological Survey. Every municipality and rural water supply in the MWSI has been updated through communication with DNR field offices, consultants, municipalities, and others. Historical and current water quality analyses are linked with information on active and abandoned municipal wells. The WIT will be a dynamic database providing scientists with an interactive system to conduct water-quality research.