The Minnesota Department of Agriculture’s groundwater nitrate testing and evaluation program is targeted to sensitive areas of the state. An area is considered sensitive if the groundwater is prone to contamination. The goal is to develop a broad knowledge of nitrate in drinking water wells (public and private).
Nitrate data is collected from public and private wells in sensitive areas. The samples are tested and the results are summarized.
Private wells are voluntarily tested through the Township Testing Program and the Private Well Network. The MDA does follow-up visits, if necessary, to confirm the results from the Township Testing Program.
Next, the results are evaluated. The MDA reports the overall pattern of nitrate levels in wells within defined areas. The testing results are the basis for taking action as described in the Nitrogen Fertilizer Management Plan.
The Minnesota Department of Health (MDH) is responsible for monitoring pollution in public wells within wellhead protection areas (WHPAs), including nitrate. The MDA coordinates with the MDH to obtain monitoring data from public water suppliers that collect nitrate samples.
The MDA and the MDH evaluate the nitrate results to determine if they meet the screening criteria and are the most representative of the raw water. The samples could include raw water, finished water, or water from other area wells; however raw water is more appropriate for understanding actual nitrate conditions. If the opportunity exists, nitrate data from private wells within WHPAs will be considered as well.