Just because your water is “clear” doesn’t mean it’s clean. Some drinking water contaminants are colorless and odorless—including nitrate. Excess nitrogen and nutrient pollution have been putting our water supplies at risk for decades. These tricky contaminants require more powerful filtration systems too. Fortunately, certain home water filters can help remove contaminants that the city’s treatment plant might have missed, like nitrate.

What is nitrate?

Nitrogen enters our soil naturally from decaying plants and animal products, but it’s also a main ingredient in fertilizer. When the bacteria in soil get in contact with nitrogen, they convert it into the nitrogen/oxygen ion nitrate.

How does excess nitrogen and nitrate enter our water supply?

Plants love getting nitrogen in the nitrate form because it’s easier to absorb. The problem with nitrate though, is that also moves easily through water and soil.

With lots of rainfall and high nitrogen-nitrate levels, an area’s groundwater and ecosystem can quickly become contaminated. When compared to the rest of the country, Indiana has a remarkably high risk of increasing groundwater contamination with nitrate.

That nutrient pollution happens when there’s too much nitrogen or phosphorus in the water. Problems with sewer and septic systems can contaminate our source water, but the issue is usually with fertilizer. Fertilizer runoff from agricultural areas and suburban lawns put more nitrogen back into our water supply, and the ecosystem can’t handle the increase.

What are the health risks associated with nitrate in drinking water?

When someone ingests nitrate, their body converts it to another nitrogen form: nitrite. Nitrate and nitrite can have toxic effects because they interfere with the body’s process of transporting oxygen through blood. Methemoglobinemia, also known as blue baby syndrome, is directly linked to nitrate exposure in drinking water.

High nitrate levels are connected to cancer risks, thyroid issues, and other birth defects too. Nitrate is especially concerning because it’s tasteless, odorless, and colorless. It’s one of the drinking water contaminants that you won’t even notice is there. The only way to know your water is safe is to have it tested or to filter it right at your tap.

What regulations are in place to prevent nitrate contamination?

The Environmental Protection Agency (EPA) sets standards for our drinking water, but many groups believe that the nitrate level isn’t strict enough. The maximum contaminant level (MCL) for nitrate-nitrogen is currently 10 mg/L. But according to the Environmental Working Group, this standard has no safety factor.

Water and food standards typically use a 10 fold susceptibility safety factor for toxicants, but the nitrate standard isn’t set the same way. We don’t know how little nitrate can put babies and children at risk. So it’s impossible to set a “safe” standard for the contaminant in our drinking water.

But my tap water is treated—why would it be contaminated with nitrate?

Nitrate levels in Westfield, Indiana measured at the top of the allowable limit—10 mg/L—in the 2014 drinking water report. So yes, even treated tap water can contain nitrate. Plainfield’s water had the same maximum nitrate ratings. Johnson County and Greenwood water also measured 10 mg/L for nitrate in their annual report for 2015. Long story short, even after the city treats the drinking water most homes need a filtration system to keep the contaminants out.

What’s the best drinking water filter for removing nitrate?

The best filter for removing drinking water contaminants is a reverse osmosis (RO) system. Unlike basic pitcher filters, reverse osmosis will filter your water through multiple stages to effectively remove nitrate. RO units get installed right underneath your kitchen sink. They can even filter out other tough pollutants like lead and pesticides from your tap water.

For the majority of Indiana’s Public Water Systems, nitrate levels are only monitored on an annual basis. If you want a more consistent water treatment process, a home RO filtration system can help keep your family’s drinking water safe—and its nitrate levels at an all-time low.