Nitrate is found in groundwater throughout Minnesota. This map shows the approximate locations of all public water systems in the state that get drinking water from a groundwater source and had at least one test for nitrate that was at or above 3 milligrams per liter, or mg/L, between 2009 and 2018. The data comes from the U.S. Environmental Protection Agency’s Safe Drinking Water Information System.
The map includes both community and non-community systems. Community systems mainly serve places where people live, like cities and towns, whereas non-community systems are places people visit, like campgrounds, churches and gas stations.
Clicking on a point brings up the name of the system, whether it is community or non-community, the county where the system is located, the population served by the system, the total nitrate tests conducted by the system between 2009 and 2018, and the number of tests at or above 3, 5 and 10 mg/L.
The yellow points represent systems that have at least one nitrate test at or above 3 mg/L. The light orange points show systems with at least one test at or above 5 ppm. Dark orange points show systems with at least one test at or above 10 mg/L, the legal limit for nitrate in public drinking water.
The gray part of the map shows where groundwater aquifers in the state are highly susceptible to contamination. This information comes from the Minnesota Geospatial Commons. Eighty-nine percent of the public water systems that had at least one test at or above 3 mg/L were within one mile of a highly vulnerable groundwater area.
To see the full methodology, click here.