Nitrate-nitrogen (referred to as nitrate) is a water soluble compound made up of nitrogen and oxygen. It can occur naturally in groundwater at levels typically in the range of 0 to 3 parts per million (ppm). Human activities such as sewage disposal, livestock production, and crop fertilization can elevate the level of nitrate in groundwater.
The drinking water standard for nitrate is 10 ppm; above this level nitrate can have negative effects on human health, specifically infants under the age of six months. Nitrate contamination above the drinking water standard is most commonly found in aquifers that are vulnerable to contamination from the land surface, such as sand and gravel aquifers and fractured bedrock aquifers. Areas with heavy row crop agriculture and vulnerable groundwater are especially at risk.
The Minnesota Department of Agriculture (MDA) conducted a major revision of the Nitrogen Fertilizer Management Plan (NFMP) in March 2015. The plan calls for an assessment of nitrate-nitrogen concentrations in private wells at the township scale. The MDA has identified townships throughout the state that are vulnerable to groundwater contamination and have significant row crop production. The schedule of testing for these prioritized townships is included on the map to the right. Townships that are not highlighted may also be considered if there is data to suggest there is a local groundwater problem.
More than 70,000 private well owners will be offered nitrate testing in over 300 townships (35 to 59 townships per summer) by 2019. This work will be done in partnership with local governments across the state.
Remember, private wells should be tested for bacteria at least once a year and for nitrate every year or every other year. A Minnesota Department of Health certified water testing lab can provide nitrate and bacteria testing services. Search for a certified lab nearest you.
Homeowners in the identified townships will receive a sampling kit in the mail. The water sample will be collected by the homeowner and sent to the certified lab (in the prepaid mailer). If nitrate is detected in the water sample, the homeowner may be offered a subsequent test for pesticides. A trained professional will come to your house to collect the water samples for pesticide analysis. Program participants information (name, address and phone number) will remain confidential.
Frequently Asked Questions: follow this link to read questions and answers about this program and for more information about the MDA's response to nitrate in groundwater.
The MDA works with Soil and Water Conservation Districts (SWCDs) and counties to coordinate the testing program in the identified townships. Funding is available to help implement the program. Priority will be given to SWCDs/counties that exhibit the ability and enthusiasm to participate and complete the work.
SWCDs/counties will gain knowledge about the current nitrate conditions in their county to enable more informed local planning and decision-making.
A total of 167 townships in 19 counties have been sampled to date (2013-2016). Counties that have participated are listed. The number in parenthesis indicates the number of townships sampled in that county. Counties include: Becker (3), Benton (4), Dakota (15), Dodge (7), Douglas (9), Hubbard (6), Kandiyohi (4), Morrison (11), Nobles (4), Olmsted (11), Otter Tail (32), Pope (6), Rock (7), Sherburne (6), Stearns (14), Todd (9), Wadena (4), Washington (2) and Winona (13). For more information, please contact Kimberly Kaiser.
Results from individual wells are sent directly to the well owner (homeowner), along with a letter explaining the results.
After the MDA receives all the well testing results in a township, the data is analyzed and information about well depth, well age and well construction is reviewed. In some cases, visits to wells may be needed to confirm results. After the analysis is complete, the MDA writes a summary document and sends it to the local partner (county, SWCD, health department). After the local partner has had a chance to review results and share the information with their community, summary documents will be posted on this web page. The MDA uses the final results to determine if additional action is needed, as described in the Minnesota Nitrogen Fertilizer Management Plan (NFMP).
Kimberly.Kaiser@state.mn.us ~ 651-201-6280
Fertilizer Section Manager
Bruce.Montgomery@state.mn.us ~ 651-201-6178