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Home > Protecting Our Lands & Waters > Clean Water Fund > Groundwater & Drinking Water Protection > Private Well Pesticide Sampling Project > Who, How, Why Participate

Private Well Pesticide Sampling Project: Participation


The Private Well Pesticide Sampling (PWPS) Project is a follow-up testing program to the Minnesota Department of Agriculture Township Testing Program. Homeowners in selected townships are offered the opportunity to first test their private drinking well for nitrate. If nitrate is detected in their first sample, homeowners are offered a follow-up pesticide test as part of the PWPS project. The testing is offered at no cost to the homeowner. Townships are selected based on the areas vulnerability to groundwater contamination and the amount of land in row crop Map of townships sampled or proposed to be sampled as part of the Private Well Pesticide Sampling Program in Minnesota.production.   

County Participation

Counties and townships are selected using the techniques defined in the 2018 Project Work Plan. Please see the MDA Contact information below to request an electronic copy of the work plan.

Sampling completed

2014-2015: Benton, Dakota, Morrison, Olmsted, Stearns, Sherburne, Wadena and Washington Counties

2016: Otter Tail, Pope, Sherburne and Morrison Counties

2017: Becker, Benton, Dodge, Douglas, Hubbard, Kandiyohi, Nobles, Rock, Todd and Winona Counties

Sampling in process

2018: Clay, Fillmore, Goodhue, Rice and Wabasha Counties

Sampling proposed

2019: Blue Earth, Brown, Carver, Chippewa, Chisago, Clearwater, Cottonwood, Faribault, Houston, Kanabec, La Sueur, Lincoln, Lyon, Meeker, Nicollet, Pipestone, Polk, Scott, Steele, and Wright Counties

2020: Big Stone, Freeborn, Lac Qui Parle, Mower, Redwood, Swift, Traverse, Waseca, Watonwan, and Yellow Medicine Counties


The information gained from this testing is valuable to the homeowner and Minnesota Department of Agriculture. The homeowner learns more about the current nitrate and pesticide conditions in their well. The Minnesota Department of Agriculture learns the localized nitrate and pesticide results to enable more informed local planning and decision-making to protect groundwater.

The Minnesota Department of Agriculture has evaluated the relationship between nitrate and pesticides in monitoring wells and in drinking water wells. In general, the probability of detecting pesticides in a well increases as nitrate concentration increases. When levels of nitrate are above 3 mg/L (ppm), there is a high likelihood that pesticides will be present. However, the relationship between nitrate and pesticide concentrations is less clear. Having a high concentration of nitrate in your water does not necessarily mean the pesticide concentration will also be high. It is also possible to have low, or no detectable nitrate in your water and still have pesticides present. Even though pesticide concentrations in groundwater rarely exceed drinking water standards in Minnesota, there are uncertainties about the health risks associated with consuming water that contains a mixture of pesticides and nitrate.


Man with safety goggles filling a glass sample bottle from an outside faucet on the side of a house.Homeowner Responsibilities to Participate

  • If you have been selected for testing, complete the PWPS Project consent form.
  • Allow MDA hydrologists on your property to collect pesticide and nitrate samples from your outside water faucets.
  • Participate in a homeowner survey about the well information and potential nitrate sources.

MDA Responsibilities

  • Provide supplemental funding for the program.
  • Assist with local coordination.
  • Collect samples according to protocol and submit to contracted laboratory for analysis.
  • Manage and organize results. 
  • Conduct statistical analysis and data summary.

PWPS Project Results

MDA Contact

Jeff Paddock