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The Groundwater Retrieval Network

The Groundwater Retrieval Network (GRN) reports well information and well sample result data from several DNR databases. GRN can help you find information about an individual well or analyze regional or statewide groundwater conditions.

Well information

  • Search the well inventory for wells in a whole county or watershed or individual wells if you know the Wisconsin Unique Well Number (WUWN).

Groundwater quality analytical data

  • Sample history report shows where specific groundwater pollutants occur statewide or shows data for specific wells if you know the approximate location of the well or its Wisconsin Unique Well Number (WUWN).
  • Sample summary count report gives a summary of substances present in groundwater by county, watershed or specific location.
  • Nitrate penetration graphs show the nitrate sample results compared to well construction and aquifer characteristics in graphical format by township and range.

Can't find the information you are looking for?

Find Private Well Construction Reports

About the data in GRN

GRN consolidates and delivers the following well information and well sample results:

  • public drinking water supply well data from the early 1970s to present from DNR's drinking water data system,
  • private drinking water supply wells, non-point source priority watershed projects and special groundwater studies data from 1988 to present,
  • landfill monitoring wells from the mid-1970s to present that have been entered into DNR's Groundwater and Environmental Monitoring System (GEMS), and
  • monitoring wells at wastewater treatment facilities and land treatment sites from the mid-1970s to present from DNR's System for Wastewater Applications, Monitoring and Permits (SWAMP).


  1. Additional data from the Leaking Underground Storage Tank (LUST), spills and remediation sites may be found in site-specific files. Use the Bureau for Remediation and Redevelopment Tracking System (BRRTS) to identify files that may contain additional data.
  2. The exact locations of public wells and high capacity wells are not available online for security reasons. If you need more detailed locations of public and high capacity wells, contact the Public Water Engineer. For more detailed information about private wells go to Find Private Well Construction Reports or contact .
  3. Some of the samples retrievable through this system are groundwater prior to treatment and some are groundwater after treatment. For example, some samples from public wells might be taken after treatment and private well samples might be taken at a tap after softening or other home treatment.
  4. You will get an error message if the search criterion returns too many records to display. Please use additional search criteria options to reduce the number of records per retrieval.
  5. See the GRN glossary for a list of terms used in GRN and their definitions.