MENOMONIE, Wis. — Dunn County officials want 300 people with private wells to have their water tested free for nitrates this summer.

“The well water sample will be analyzed for nitrates by the Dunn County Health Department Water Lab, and for this specific program, this is done at no cost to the participant,” said Heather Wood, Dunn County water resources specialist.

The testing is open to anyone with a well within Dunn County, she said, and “our goal is 300 samples with a mix of new folks as well as repeat samples.”

Any Dunn County resident with a private well is eligible to participate. County staff will visit each participating property, collect a water sample and bring it to the laboratory for nitrate analysis at no cost to the homeowner.

This is the fourth year in a row that the county has offered this free service. A massive effort in 2023 sampled 995. Follow up programs had goals to test 300 wells annually.

The regular testing is helping establish water quality data for the county as a whole. The Dunn County Well Water Quality Map is available on the Dunn County website. The map does not identify participants or individual well tests but instead shows general trends down to the section level of detail.

“This program gives us a better understanding of groundwater conditions across the county while giving residents valuable information about their own wells,” Wood said. “The more households that participate, the stronger and more useful our data becomes.”

High nitrates, for example, tend to be more common in the southeastern corner of the county, Wood said, which isn’t surprising given the sandy soils in the area.  Nitrates often result from agricultural runoff, septic systems and fertilizers.  

Each well owner will receive their results with a letter from the county Land and Water Conservation Division, explaining those results and what resources are available if there is contamination that needs to be mitigated. Dunn County cannot mandate or fund private water treatment systems or the replacement of any wells that have high test results through this program. 

Those who wish to participate in the 2026 program can sign up at https://dunncountywi.seamlessdocs.com/f/groundwaterform or contact Wood directly by calling or text at 715-619-7150 or email hwood@dunncountywi.gov.