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Indiana Department of Environmental Management

IDEM > Your Environment > Source Water Protection - Drinking Water > Statewide Ground Water Monitoring Network Statewide Ground Water Monitoring Network


In 2008, the Indiana Department of Environmental Management (IDEM) Ground Water Section began collecting untreated water samples from ground water wells statewide as part of a Ground Water Monitoring Network (GWMN). The project includes over 150 public water supply wells and almost 200 residential wells. A large percentage of Hoosiers drink residential well water that is not regulated by the Safe Drinking Water Act, and this was the impetus for starting the GWMN in Indiana.

In addition, Section 305(b) of the Clean Water Act requires IDEM to assess ground water quality, and the GWMN is included in the Indiana Integrated Water Monitoring and Assessment Report. Also, ground water monitoring is included in the Indiana Water Quality Monitoring Strategy (fact sheet available on the IDEM Fact Sheets page), and the GWMN will help fill the gap in monitoring ground water quality.


With the GWMN, IDEM seeks to:

  1. Determine the quality of ground water in the state’s aquifers;
  2. Identify and expand sampling in areas with notable contamination; and,
  3. Provide interested parties access to the ground water sampling data.


Sampling occurs annually, usually during the summer, spring or fall. IDEM samples for over 400 parameters. All wells are sampled for the National Drinking Water Contaminants, which include the following categories: volatile organic compounds, synthetic organic compounds, and inorganic compounds.

In addition, IDEM also samples for pesticide breakdown products, which are not regulated.


Results, show constituents, such as nitrates [JPG] [PDF] and arsenic [JPG] [PDF], present across the state in areas of varying hydrogeological sensitivity. Continued annual sampling will give IDEM an opportunity to explore trend analysis, seasonal variations, and the relationship between sensitivity and hydrogeological setting. For more detailed review, our annual report summaries will posted soon.

Annual Sample Results (Section Centroid Locations Only):

If you need more site specific data, please IDEM at (317) 232-8488, or via email at "info at".


Additional Information: