Minnesota State Wire

The Minnesota Department of Agriculture (MDA) conducted free nitrate testing for private well owners at Farmfest this year, marking the first time the service was offered at the event. Over three days, 107 wells were tested. Of those, six wells exceeded the federal health standard for nitrate-nitrogen, which is set at 10 milligrams per liter (mg/L), while another nine wells showed elevated levels between 5 and 10 mg/L.

According to MDA Commissioner Thom Petersen, “Unsafe nitrate levels can be a hidden danger in Minnesota well water. At Farmfest, we uncovered those risks and gave families immediate answers to protect themselves.”

Nitrate contamination in drinking water poses health risks, particularly for infants under six months old and pregnant women. Because nitrate cannot be detected by smell or taste, regular testing is necessary to determine its presence and concentration. The Minnesota Department of Health recommends annual testing of private wells for nitrate and other contaminants.

The MDA oversees nitrogen fertilizer use as part of the state’s Groundwater Protection Rule. This rule aims to address nitrate levels in public wells and limits fertilizer application during certain times of year—specifically in the fall and on frozen soils—to help prevent groundwater contamination.

Under Minnesota’s Groundwater Protection Act, the MDA manages nitrogen fertilizer use through its Nitrogen Fertilizer Management Plan. The plan seeks to prevent or reduce nitrate impacts on groundwater sources across the state.

At Farmfest, some families learned that their water was unsafe due to factors such as shallow or poorly constructed wells, proximity to crop fields or manure sources, and local geology like fractured limestone found in southeast Minnesota’s karst region—all common contributors to nitrate contamination.

Denton Bruening, a water-quality expert who led the testing clinic at Farmfest, said: “One young family with a newborn learned their water wasn’t safe. They left our booth with both answers and options—that’s the power of this program.”

For those whose wells had elevated nitrate levels, MDA staff provided guidance on treatment options including reverse osmosis or distillation systems. In some cases where immediate action was needed, alternative water supplies were recommended.

Since introducing free nitrate testing more than thirty years ago, the MDA has tested tens of thousands of wells throughout Minnesota. In 2024 alone, over 2,400 wells were tested statewide; about 6% exceeded federal health standards for nitrates. The program not only provides testing but also connects well owners with solutions such as continued monitoring or considering new well construction if needed.

“The response at Farmfest shows how valuable this service is,” Petersen added. “Every Minnesotan deserves safe drinking water, and free clinics like this are one way we make that a reality.”

To expand access to testing services across Minnesota communities, the MDA maintains equipment in partnership with local Soil and Water Conservation Districts as well as organizations like the Minnesota Well Owners Organization. Community groups interested in hosting similar clinics are encouraged to contact Denton Bruening at 651-261-1993 or Travis Hirman at 612-201-4194 for more information.