Free nitrate screening events offered across Southeast Minnesota
The Olmsted Soil and Water Conservation District (SWCD) and Olmsted County Public Health Services (OCPHS) invite private well owners to participate in free nitrate screening events this summer.
Regular testing is a key step in maintaining safe drinking water. Free nitrate screenings offer well owners an easy opportunity to check for contamination and learn about potential next steps.
Summer 2026 water testing event details
Winona County Fair
- July 10 from 1 to 4 p.m.
- July 11 from 11 a.m. to 1 p.m.
Wabasha County Fair
- July 17 from 2 to 6 p.m.
Fillmore County Fair
- July 22-24 from 10 a.m. to 3 p.m.
Olmsted County Fair
- July 30 from noon to 3 p.m.
- July 31 from 3 to 6 p.m.
Goodhue County Fair
- August 13-14, from noon to 4 p.m.
To take part in a free nitrate screening, residents should collect a cup of water from their private well using a clean glass container. They should bring it to the screening booth at a designated event. Samples will be analyzed on-site, and results will be provided within approximately 15 minutes.
Staff will be available to answer questions, help interpret results, and offer guidance if elevated nitrate levels are detected.
Why nitrate screening matters
Nitrate is a compound formed when nitrogen combines with oxygen or ozone. While nitrogen is essential for life, elevated nitrate levels (10 mg/L or above) can pose health risks. Infants and pregnant individuals are especially vulnerable.
Nitrate can enter groundwater naturally, but high levels in private wells often result from human activity. Common sources include:
- Improper well construction or location.
- Runoff from fertilizers.
- Septic system leakage.
- Animal feedlots.
- Industrial or food‑processing waste.
Wells can be vulnerable, particularly if they are shallow, poorly constructed, or submerged for long periods.