Illinois has an abundance of groundwater resources that supply millions of gallons of water per day to public, irrigation, and commercial/industrial systems. Groundwater resources are unevenly distributed throughout Illinois due to the state’s complex bedrock and glacial geology. This interactive map depicts the three major aquifer systems in Illinois and the public water supply (PWS) wells that extract groundwater from them. Users can select or query wells based on spatial location or attribute, and then can view reported withdrawals in an attribute table or in graph view. Users can also export data found in the attribute tables as a CSV file and can output maps in various formats for printing.

The withdrawals reported in the attribute tables and graphs are the total withdrawals at each well in gallons/year and are reported through the Illinois Water Inventory Program. The latest complete dataset available for public water supplies is from 2013 and will be updated as they are finalized. Users should note that not all facilities have reported every year, therefore withdrawals may be missing at some wells for a particular year.

The three aquifer systems depicted are the major sand and gravel aquifers, the shallow bedrock aquifers, and the Cambrian-Ordovician sandstone aquifers. Aquifer maps were developed by the Illinois State Geological Survey, and are available for download. Major aquifers are considered to be at least 50 square miles in area and are capable of yielding at least 70 gallons per minute to wells.

If you have any problems with the map’s functionality, please contact Daniel Hadley by email drhadley@illinois.edu or phone (217) 300-0402.