Private wells in Southeast Minnesota

Nitrate is a health concern in some private wells in southeast Minnesota

 

Addressing nitrate in private wells in southeast MN 

This webpage provides private well test results for nitrate in Dodge, Fillmore, Goodhue, Houston, Mower, Olmsted, Wabasha, and Winona counties (referred to as Southeast Minnesota). It also includes key metrics to measure the State of Minnesota’s progress in implementing their work plan for Addressing Nitrate in Southeast Minnesota. Learn more about this work plan and why it exists at Response to EPA Nitrate Letter for Southeast Minnesota. 

How to protect yourself and your family 

If your drinking water comes from a private well, you should test for nitrate every year. 

The U.S. Environmental Protection Agency (EPA) standard for nitrate in drinking water is 10 milligrams of nitrate (measured as nitrogen) per liter of drinking water (mg/L). 1 milligram per liter (mg/L) is the same as 1 part per million. Based on the data available at this time, this standard protects infants against methemoglobinemia. Infants are the most sensitive group of people for known health effects.

Health effects of nitrate 

Consuming too much nitrate can affect how blood carries oxygen and cause methemoglobinemia (also known as a blue baby syndrome). Bottle-fed babies under six months old are at the highest risk of getting this illness. Methemoglobinemia can result in serious illness or death. It can cause the lips and skin to turn a bluish color but may be difficult to detect in infants. Symptoms will often resolve once the nitrate source is removed. People with glucose-6-phosphate-dehydrogenase deficiency or other metabolic conditions may be at higher risk of getting this illness.

Science has emerged recently describing possible health impacts of long-term exposure to nitrate in drinking water at concentrations below the current regulatory standard. Potential health impacts include associations with thyroid problems, adverse pregnancy outcomes, and cancers (particularly colorectal). Further research is necessary to confirm these observations. Minnesota Department of Health (MDH) continues to follow the research and will provide updated guidance when adequate data are available.

Nitrate is a health concern in some private well water in southeast Minnesota 

Data from the Southeast Minnesota Water Analysis laboratory show that 5.1% of private wells in Southeast Minnesota that have tested through the laboratory since 2016 have a nitrate concentration at or above 10 mg/L. Results are updated quarterly. 

The data also show that 15.6% have a nitrate concentration above 3 mg/L (but less than 10 mg/L). While those levels are below the 10 mg/L standard for drinking water, they do suggest human-made sources of nitrate have gotten into the water and the level could increase over time. Testing the water every year is important. 

Finally, the data show that 79.3% have a nitrate concentration below 3 mg/L or is not detected.  

Measuring progress  

Minnesota has a robust work plan to address nitrate in southeast Minnesota, including offering free well testing and mitigation for eligible households and conducting a well inventory. We are doing this work in phases. As we add components to the work, we will add measures to show how the work is advancing. 

Data source 

  • Southeast Minnesota Water Analysis Laboratory

Last updated October 2024