Nitrate Risk: The maps and data below display estimated nitrate contamination risk across Minnesota. Homes on private wells are considered to be at increased risk of nitrate contamination if the wells are:

  1. Located in areas with significant row crop agriculture and vulnerable geology; or

  2. Located in a township where more than 10% of wells tested by the Minnesota Department of Agriculture (MDA) were found to have nitrate levels above the federal drinking water standard of 10 mg/L.

  • Number of homes on wells at increased risk (County)
  • Percent of homes on wells at increased risk (County)
  • Number of homes on wells at increased risk (Census tract)
  • Percent of homes on wells at increased risk (Census tract)

Estimated number of homes on private wells at increased nitrate contamination risk by county, 2022

Central and southeast counties have a higher number of homes on wells at increased risk in due to widespread crop production combined with vulnerable geology (sand-gravel and fractured bedrock aquifers).

Nitrate contamination can come from localized sources and change over time. Shallow, poorly sealed, and improperly constructed or sited wells are especially vulnerable. MDH recommends that all private wells are tested for nitrate every year regardless of nitrate risk levels shown here. Data sources: Minnesota Department of Revenue Property Record Information System of Minnesota data system (PRISM), MDH Drinking Water Protection Program (community water system service area boundaries), U.S. Department of Agriculture 2022 crop-specific land cover data for Minnesota, Minnesota Department of Natural Resources Pollution Sensitivity of Near-surface Materials, and Minnesota Department of Agriculture Township Testing Program. See “About the Data” for more information.
Display ID
Topic
Subtopic
Datafeed
Year
Month
Geo ID
Geography
Geo Name
Variable
Category
Measure
Value
Count
Total homes on private wells
Note
Upper CL
Lower CL
Label
Number at increased risk due to land use and geologic factors
Number at increased risk based on nearby well testing for nitrate
Number lower risk
Number missing

    Estimated percent of homes on private wells at increased nitrate contamination risk by county, 2022

    A higher percent of homes on wells at increased risk are located in central and southeast Minnesota counties due to widespread row crop production combined with vulnerable geology (sand-gravel and fractured bedrock aquifers). The southwest corner of the state also has areas of geologic vulnerability (sand-gravel aquifers) and intensive row crop agriculture, though the total number of homes on wells in this area is relatively low.

    Nitrate contamination can come from localized sources and change over time. Shallow, poorly sealed, and improperly constructed or sited wells are especially vulnerable. MDH recommends that all private wells are tested for nitrate every year regardless of nitrate risk levels shown here. Data sources: Minnesota Department of Revenue Property Record Information System of Minnesota data system (PRISM), MDH Drinking Water Protection Program (community water system service area boundaries), U.S. Department of Agriculture 2022 crop-specific land cover data for Minnesota, Minnesota Department of Natural Resources Pollution Sensitivity of Near-surface Materials, and Minnesota Department of Agriculture Township Testing Program. See “About the Data” for more information.
    Display ID
    Topic
    Subtopic
    Datafeed
    Year
    Month
    Geo ID
    Geography
    Geo Name
    Variable
    Category
    Measure
    Value
    Count
    Total homes on private wells
    Note
    Upper CL
    Lower CL
    Label
    Number at increased risk due to land use and geologic factors
    Number at increased risk based on nearby well testing for nitrate
    Number lower risk
    Number missing

      Estimated number of homes on private wells at increased nitrate contamination risk by census tract, 2022

      A higher number of homes on wells at increased risk are in central and southeast Minnesota census tracts due to widespread crop production combined with vulnerable geology (sand-gravel and fractured bedrock aquifers) in these regions.

      Results are not presented (suppressed) if there are less than five estimated homes on wells in a census tract. Nitrate contamination can come from localized sources and change over time. Shallow, poorly sealed, and improperly constructed or sited wells are especially vulnerable. MDH recommends that all private wells are tested for nitrate every year regardless of nitrate risk levels shown here. Data sources: Minnesota Department of Revenue Property Record Information System of Minnesota data system (PRISM), MDH Drinking Water Protection Program (community water system service area boundaries), U.S. Department of Agriculture 2022 crop-specific land cover data for Minnesota, Minnesota Department of Natural Resources Pollution Sensitivity of Near-surface Materials, and Minnesota Department of Agriculture Township Testing Program. See “About the Data” for more information.
      Display ID
      Topic
      Subtopic
      Datafeed
      Year
      Month
      Geo ID
      Geography
      Geo Name
      Variable
      Category
      Measure
      Value
      Count
      Total homes on private wells
      Note
      Upper CL
      Lower CL
      Label
      Number at increased risk due to land use and geologic factors
      Number at increased risk based on nearby well testing for nitrate
      Number lower risk
      Number missing

        Estimated percent of homes on private wells at increased nitrate contamination risk by census tract, 2022

        Central and southeastern Minnesota census tracts have a higher percent of homes on wells at increased risk due to widespread crop production combined with vulnerable geology (sand-gravel and fractured bedrock aquifers). The southwest corner of the state also has areas of geologic vulnerability (sand-gravel aquifers) and intensive row crop agriculture, though the total number of homes on wells in this area is relatively low.

        Results are not presented (suppressed) if there are less than five homes on wells in a census tract. Nitrate contamination can come from localized sources and change over time. Shallow, poorly sealed, and improperly constructed or sited wells are especially vulnerable. MDH recommends that all private wells are tested for nitrate every year regardless of nitrate risk levels shown here. Data sources: Minnesota Department of Revenue Property Record Information System of Minnesota data system (PRISM), MDH Drinking Water Protection Program (community water system service area boundaries), U.S. Department of Agriculture 2022 crop-specific land cover data for Minnesota, Minnesota Department of Natural Resources Pollution Sensitivity of Near-surface Materials, and Minnesota Department of Agriculture Township Testing Program. See “About the Data” for more information.
        Display ID
        Topic
        Subtopic
        Datafeed
        Year
        Month
        Geo ID
        Geography
        Geo Name
        Variable
        Category
        Measure
        Value
        Count
        Total homes on private wells
        Note
        Upper CL
        Lower CL
        Label
        Number at increased risk due to land use and geologic factors
        Number at increased risk based on nearby well testing for nitrate
        Number lower risk
        Number missing