Nitrates are compounds of nitrogen and oxygen molecules that occur naturally in the environment. According to the CDC's West Testing webpage, nitrate in your well water can come from animal waste, private septic systems, wastewater, flooded sewers, polluted storm water runoff, fertilizers, agricultural runoff, and decaying plants. High levels of nitrates in your well water can be harmful, especially for infants and pregnant women.

Nitrate is listed as a primary contaminant by the USEPA because high levels of nitrates can have potential health effects. Elevated nitrate levels can lead to a condition known as methemoglobinemia, or ‘blue baby syndrome,’ which impairs red blood cells’ ability to transport oxygen. This is particularly perilous for infants under six months old.

The USEPA recommends removing nitrate if greater than 10 milligrams per liter (mg/l) to prevent these issues from occurring in the water coming into your home. To ensure you are protecting your family’s health, we have developed a set of recommendations for testing that are provided in our article, "What do I need to know about sampling my well water?" , that includes nitrate. When testing your well water you will very rarely be testing for only one thing, like nitrate, and instead testing for a suite of constituents that are important to identify if in your drinking water.

Once you test and have decided to treat your water to remove nitrate, the Minnesota Department of Health has developed a Home Water Treatment Guide that covers treatment for any common constituent in well water. The most important advice we can provide you is if you are going to add treatment to your home water system, be sure the treatment device has been certified to remove nitrate by an independent third-party certification organization.

Coliform and Nitrate Information for Private Well Owners, May 2010, Washington Department of Health.

Hassinger, E., Doerge, T., and Baker, P., Water Facts: Number 6 Reverse Osmosis Units, February 1994, Arizona Cooperative Extension.

Yaragal, R.R., Mutnuri, S. Nitrates removal using ion exchange resin: batch, continuous column and pilot-scale studies. International Journal of Environmental Science and Technology. 20, 739–754 (2023).