A recent study of private water wells in Dakota County, funded by the Clean Water, Land and Legacy Amendment through the Minnesota Department of Agriculture, found nitrate levels in some wells that were above the safe drinking water standard. According to the Minnesota Department of Health (MDH), water with a nitrate concentration of more than 10 milligrams per liter is unsafe for infants and pregnant women to drink.
During its “Targeted Townships” study, the County sampled water from private wells in a dozen communities — the cities of Coates, Hampton, and Hastings, and the townships of Castle Rock, Douglas, Hampton, Marshan, Nininger, Randolph, Sciota, Vermillion, and Waterford — and discovered that 226 of the 742 wells tested exceeded the 10 mg/L standard. Nitrate is a common byproduct of nitrogen fertilizers, which can leach into groundwater and increase the nitrate levels in private wells.
The “Targeted Townships” results spurred Dakota County’s Environmental Resources and Public Health departments to launch Test the Waters, a campaign encouraging residents with private wells to have their water tested regularly, ensuring safe water for everyone from infants to adults.
As part of the campaign, residents will have the opportunity later this spring to get their well water tested for nitrates at no cost. Residents who have private wells with high nitrate levels can reduce contamination by installing a reverse osmosis treatment system. However, even with a home treatment system, MDH recommends infants younger than six months not drink well water or formula made with well water that had tested high for nitrate in the past.
Most county residents get drinking water from municipal water systems that are tested regularly by MDH and have safe levels of nitrate.
For more information about nitrate in drinking water and to learn more about the “Targeted Townships” study, go to the Wells and Drinking Water page.