Know Your Water Contaminants: Nitrate

Cow in Field

If you own a private well that supplies your home, you’re already intimately aware of the need to be vigilant when it comes to testing and protecting your drinking water. Instead of relying on a municipality to monitor and remove contaminants, it’s up to you to keep your water safe. While testing and maintaining your well regularly is the best defense against contaminants, there are some outside influences that can affect the source of your water that are beyond your control.

One of the main contaminants the EPA defines as an issue to be aware of with well water is nitrates. It is an odorless, tasteless, and colorless contaminant commonly associated with industrial agriculture.

What Are Nitrates?

While nitrate can occur naturally in the environment from the bacterial breakdown of nitrogen, high levels in groundwater are normally the result of human influence, specifically in areas where industrial agriculture operations are prevalent. Nitrate is found in all animal waste and fertilizers. As livestock manure and chemical fertilizers are applied to crops in large concentrations, nitrate seeps through soil during rainfall and eventually makes its way into groundwater sources. Private wells that draw from these groundwater sources can then become contaminated with elevated nitrate levels as it continues to concentrate.

Poorly maintained septic tanks are also major culprits of nitrate contamination. Human waste, much like the natural and chemical fertilizers used in farming applications, contains large amounts of nitrate. While a single leaking septic tank doesn’t produce as much nitrate as a dairy farm with a few hundred cows, the close proximity to your well can easily introduce unwanted levels of nitrate into the water that supplies your home.

2006 United States Geological Survey (USGS) study concluded that more than one million private well owners are located in areas with groundwater risk about the federally accepted 10 mg/l MCL. A 2009-2010 report also stated that “Nitrate was the most common inorganic contaminant derived from man-made sources – such as from fertilizer applications and septic tanks – that was found at concentrations greater than the Federal drinking water standard for public water supplies (10 mg/L)”. The map below shows the areas of the highest risk of nitrate contamination based on the 2006 study.

USGS Nitrate Map

*Image courtesy of the United States Geological Survey

Shallow wells or wells that draw from a shallow aquifer are the most susceptible to nitrate contamination. Deeper, sealed wells that source their water from a deeper aquifer tend to experience less contamination, due to the difficulty for the contamination source to reach the groundwater and the resulting reduced nitrate concentration.

Effects Of Nitrate In Drinking Water

EPA guidelines state that the maximum contaminant level of nitrate is 10 mg/l for the average healthy adult to consume. Well water that is discovered to contain more than this allotted amount must be treated. While there has been some correlation between high amounts of nitrate contamination and poor health symptoms in otherwise healthy adults, nitrates rarely present any adverse health effects. But for infants younger than six months old, nitrates can seriously affect blood oxygen levels, presenting some dangerous, and even life-threatening symptoms. Parents are advised to avoid the use of any water that is suspected to contain nitrates when giving an infant younger than six months water to drink or mixing it with formula. Pregnant women should also avoid drinking or cooking with water that has any level of nitrates in it.  

Since nitrates leave behind no taste, odor, or color, it is necessary to test well water annually to detect any level of nitrate contamination. Nitrates could be introduced into your well at anytime, so even if it was tested at a safe level last year, it may have increased over time.


If you discover that your well contains levels of nitrates higher than the EPA standard, it’s time to look into treatment possibilities. The Water Quality Association has identified a number of techniques to remove nitrate, including chemical reduction, ion exchange, and reverse osmosis.

Since nitrates only pose negative effects when consumed, the most practical solution to nitrate removal is reverse osmosis. These small point of use systems connect to a dedicated drinking faucet, ensuring that every drop that you drink is free of many contaminants,  including nitrates. When looking for a reverse osmosis unit to treat nitrates, it’s important to look for certification information to make sure that it’s actually qualified to remove nitrates effectively.

Evolve’s Ultrowater reverse osmosis system is certified for the safe removal of nitrates and a list of other common contaminants from your drinking water. Commonly installed beneath the sink or in a discrete location, the Ultrowater RO uses a multi-stage filtration process that traps and removes particles and contaminants, leaving you with crystal clear drinking water you can trust.

If you’re a well water owner and are concerned about the possibility of nitrates in your water, call your nearest Evolve dealer and schedule a comprehensive water test today!

our service area

We serve the following areas

Our Locations:

Clean Water Center
1990 Prospect Ct
Appleton, WI 54914

Clean Water Center
N57W39785 Wisconsin Ave
Oconomowoc, WI 53066
Service Area
Free Quote