Nitrate Testing in Private Wells

Nitrate-nitrogen (referred to as nitrate) is a common contaminant found in many wells throughout Minnesota. Shallow wells, dug wells, and wells with damaged or leaking casings are the most vulnerable to nitrate contamination. Major sources of nitrate contamination can be from fertilizers, animal waste, and human sewage. It is highly recommended to test your drinking water supply on a regular basis.

Elevated levels of nitrate in drinking water can cause Blue Baby Syndrome in infants under six months of age and that are bottle fed. Long term health effects to older children and normal healthy adults exposed to elevated levels of nitrate in their drinking water are not yet known or agreed upon in the scientific community. However, the National Cancer Institute suggests a link between elevated levels of nitrate in drinking water and an increased risk of non-Hodgkin's lymphoma (a cancer of the lymphatic system). The study is titled "Drinking water nitrate and the risk of non-Hodgkin's lymphoma." Authors are M. H. Ward, Mark, K.P. Cantor, D. D. Weisenburger, A. Correa-Villasenor, and S. H. Zahm. Epidemiology, September 1996.

There are three main options for testing your private well water for nitrate-nitrogen:

  • Contact a certified water testing lab and follow their instructions for submitting a water samples. Nitrate analysis usually costs around $20.00.
  • Contact your county Environmental Services or Soil and Water Conservation District (SWCD) and ask if they has access to a nitrate testing machine. The Minnesota Department of Agriculture (MDA) loans nitrate testing machines to many counties so they can provide free nitrate analysis for private well owners. Water testing is provided at the local office or at a nitrate testing clinic (event).
  • Starting in 2013 and through 2019, the MDA is offering nitrate testing to 70,000 private well owners in agricultural areas with vulnerable groundwater. Learn about the Township Testing Program.

How do I collect a sample for nitrate analysis?

If you are sending a sample to a certified lab, follow instructions provided by the lab. The instructions below are for collecting a sample to take to your local SWCD or county Environmental Services office or to a local nitrate testing clinic.

To take your sample, run your cold tap for five to ten minutes then collect about one cup of water in a plastic baggie (double bag) or clean jar. Keep the water cool until arrival. You can collect the water anytime within one day of the nitrate analysis (if you are going to the local office right after work, you can collect the sample in the morning and keep it cool all day until you arrive).

Once you’ve arrived at the SWCD office or nitrate testing clinic you will submit your sample, usually wait about five minutes, and receive the results on-the-spot. If the office or event is extremely busy, the wait may extend to about ten minutes.

Do I have to give out any personal information to receive a free test?

No. However, you may be asked to fill out a voluntary survey but it is not required. Over the years, the nitrate water testing program (see information below) has gained valuable information linking well characteristics and nitrate concentrations.

Can I have more than one sample tested?

Yes. Extra samples are free too. You are encouraged to test all the wells on your property (house, barn, irrigation, etc.). Also, you may collect neighbors or relatives samples and bring them in for analysis. If you have a water treatment unit that reduces or removes nitrate such as a reverse osmosis unit or a distiller, feel free to collect a sample before treatment and after treatment to ensure the treatment system is working properly. It is not necessary to collect a sample from before and after a water softener. A softener does not reduce nitrate and the nitrate result will be the same before and after treatment.

What if I find nitrate in my drinking water?

If the level of nitrate is between 0 ppm to 10 ppm nitrate it is considered safe by the U.S. Environmental Protection Agency (EPA) and the Minnesota Department of Health (MDH). If the sample has a nitrate concentration above 10 ppm nitrate, it is critical that infants six months and younger do not drink this water in any form. Also, you should have your water re-tested at a certified water testing laboratory.

Options for well owners to reduce or remove nitrate vary depending upon type, age, and location of well. Drinking bottled water may be a good short term solution. In an effort to figure out why you may have nitrate in your water supply, do some investigating. Look at your well record from when it was installed (your county will have this info.). Is your well fairly old? Does your well have construction problems? Is it a sand point, or shallow, or hand dug? These well characteristics tend to commonly plague the owner with contamination problems. If you have concerns about your private well water, contact your local health department, or a licensed well contractor, or your nearest Minnesota Department of Health (MDH) district office.

There are water treatment units than can reduce the level of nitrate in your drinking water. However, they are an investment in both money and maintenance. Reverse osmosis, distillation, and ion exchange will reduce levels of nitrate significantly if the units are maintained properly. Keep in mind that these units can stop working at anytime without your knowledge so test your water at least every year, if not twice yearly to ensure it’s working properly. Treatment units typically cost anywhere from $400 (for just your tap water which may be all you need) to thousands of dollars (for household-wide treatment).

Annually test your water for both nitrate and bacteria. Keep a running record of all water tests performed from year to year in a file. Tracking increasing or decreasing nitrate levels through time is an excellent research tool.

Should I test my water for anything else?

Yes. The other major contaminant to test for annually is bacteria. You can have this done at a certified water testing laboratory. The cost for a bacteria test will range from $7.00 to $20.00. Contact a certified water testing lab in your area to get a bacteria test kit.

Details of the Nitrate Clinic Water Testing Program

In 1993, the Minnesota Department of Agriculture developed a "walk-in" style of water testing clinic with the goal of increasing public awareness of nitrate contamination in rural drinking and livestock water supplies. Results from the testing both educate the participants and also provide some broad information on the occurrence of nitrate 'hotspots' across the state. The clinic concept revolves around a number of simple principles: local participation is critical; testing is free to the public with immediate results; the overall program needs to be inexpensive; a non-regulatory atmosphere is important and well owners may remain anonymous; and the staff's most important goal is to provide the required technical assistance to a diverse audience of well owners.

The Nitrate Water Testing Program has provided testing services and educational outreach to over 50,000 well owners, since 1993. The concept has proven adaptable for county fairs, field day events, public school programs, and ‘stand alone’ events. Past sponsors have been the Soil and Water Conservation Districts, Minnesota Extension Service Educators, county health or environmental health services, county planning and zoning, public schools, lake associations, and farm organizations.

Between 1999 and 2006, the program was funded through the Environment and Natural Resource Trust Fund. However, in 2006, this funding ended and the program was not continued. Counties were still able to use the MDA nitrate testing equipment, but had to provide their own personnel to run the clinic and record the nitrate analysis results. In 2011 and 2012, the Nitrate Testing Clinic Program was reinstated with help of Clean Water Funds.

In 2011, over 2000 samples were analyzed during nitrate testing clinics from 41 counties across the state. Approximately 6.5 percent of all samples taken were over 10 ppm (or mg/L), which is a level considered toxic for infants and young children. The median concentration for all samples was 0.7 ppm and the maximum was 72 ppm. Counties with the greatest levels of concern were in the southwestern part of the state; Rock, Nobles, and Pipestone had the top three highest results for private wells greater than 10 ppm.

Nitrate clinics are developed for homeowner education and outreach and are not designed as a scientific study. If you would like to learn more about a statistically designed private well network please refer to Central Sands Private Well Network.

At this time the MDA does not host nitrate testing clinics, instead the MDA provides the necessary equipment to local partners who can provide free water testing at the local office or locally organized events. The local partner is responsible for their own personnel to run the clinic and recording the nitrate analysis results.