By: Mary Nesberg, Extension educator
Are you trying to remember the last time you screened your drinking water well for nitrates? The Minnesota Department of Health recommends screening for nitrates every year. There are several resources available for well users and farmers in southeast Minnesota to help improve water quality.
Southeast Minnesota’s karst geology
Residents of southeast Minnesota have many reasons to love this corner of the state — the rolling hills, limestone bluffs, and clear, spring-fed streams that define its landscape. These features exist because we live in a region shaped by karst geology, where water has carved pathways through limestone over thousands of years. It’s a landscape of beauty and complexity — but also one of vulnerability. |
| Image credit: Minnesota Pollution Control Agency |
In karst areas, fractures, sinkholes, and underground caves can allow water and pollutants to travel quickly from the surface into the groundwater below. That means contaminants like nitrates can more easily reach private wells, especially those that draw from aquifers with “younger” water in them. Fortunately, private well owners in southeastern Minnesota have access to free or low-cost testing for nitrates and other key pollutants, helping ensure their household water is safe to drink.
TAP-IN program
The TAP-IN program is a partnership between local Soil & Water Conservation Districts, county environmental and public health departments, and the Minnesota Department of Health — all working together to keep private well water safe to drink.“To keep our communities healthy, the TAP-IN program helps ensure residents have equitable access to safe drinking water," said Olmsted SWCD Conservation Technician Zack Martin. "Through this partnership, we are protecting our water sources, which helps improve the quality of life for those in southeast Minnesota."
If you live in Dodge, Fillmore, Goodhue, Houston, Mower, Olmsted, Wabasha, or Winona County and rely on a private well, you’re eligible to participate. Through TAP-IN, residents can receive free water testing kits and lab analysis for five common contaminants, including nitrate, coliform bacteria, arsenic, manganese, and lead. If your water shows high nitrate levels (above 10 milligrams per liter), you may even qualify to have a reverse osmosis system installed at no cost — a simple way to ensure your family’s drinking water stays clean and safe.
When nitrate levels are detected at those levels, adverse health effects can impact people of all ages, but can be especially harmful to infants. More information on those health impacts can be found at this link from the Minnesota Department of Health.
As of September 2025, residents in southeastern Minnesota have ordered 2,315 test kits, helping bring the TAP-IN program closer to reaching its goal of running 3,600 tests. To date, 249 reverse osmosis systems have been installed in homes where nitrate levels of 10 mg/liter or over were detected.
Upcoming events
The Olmsted Soil and Water Conservation District (SWCD) staff host several events throughout the year where private well owners may drop off a one-cup water sample, collected in a clean container, for water quality screening—with results available while they wait.
University of Minnesota Extension-Olmsted County is partnering with Olmsted SWCD to offer free nitrate screening at an upcoming crops-focused event in Rochester on February 18th. The first annual Grain Gathering will be held in Aune Hall and will explore opportunities to diversify corn-soybean systems by incorporating oats into the rotation.
Free nitrate screening will be available from 9:30 a.m. to 1:00 p.m. during the event, where participants can have access to same-day screening results. For questions related to the nitrate screening, please contact the Olmsted SWCD directly at healthyhomes@olmstedcounty.gov or 507-328-6555 . To learn more or to register for the Grain Gathering, visit z.umn.edu/GrainGathering.
Resources for farmers
Many of the farmers in southeast Minnesota are becoming more interested in incorporating conservation practices that can help limit the amount of nitrates leaching into the groundwater. For producers who farm in Olmsted County, you may be eligible to apply for a cost-share through Olmsted SWCD’s Groundwater Protection and Soil Health Program. This program was developed by the Olmsted SWCD staff in collaboration with local farmers.The time to apply is now, before any seeds are planted. The base payments for this program include practices such as:
- Planting cover crops ($55/acre)
- Alternative crops ($75/acre)
- Haying/grazing ($75/acre)
- Pasture enhancements ($30/acre)
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| Martin Larsen of Byron, Minn. has incorporated food-grade oats and clover into his corn-soybean rotation. (Photo credit: Martin Larsen) |
If you live outside of Olmsted County, check with your local SWCD for program offerings, as there may be funding available that provides similar incentives through the Regional Conservation Partnership Program.
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