62+ million people are exposed to nitrates in their tap water. Here’s how to remove it
About 62 million Americans — roughly 1 in 5 — may be drinking tap water with potentially harmful levels of nitrates in water, according to a new report from the Environmental Working Group.
The findings, drawn from nearly 50,000 public water systems across all 50 states, raise fresh questions about a federal safety standard that hasn’t been updated since 1962, even as peer-reviewed research links low-level exposure to cancers, thyroid disease and birth defects.
For families wondering whether the water flowing from their kitchen tap is safe, the EWG report offers the most detailed picture yet of where contamination is showing up — and how to remove it with a point-of-use or whole-house water filter system.
What are nitrates in water and where do they come from
Nitrates are a naturally occurring compound made of nitrogen and oxygen, found in air, water, soil and plants, according to the U.S. Environmental Protection Agency. They become dangerous when nitrogen-heavy fertilizers and livestock manure wash into groundwater, streams and rivers through rainfall and irrigation.
Contamination can travel long distances, which means cities far from farms can still be affected because their water sources are fed by rivers and streams that originate in agricultural areas.
Agriculture isn’t the only source. “While fertilizer is one source, others include organic matter mineralization, septic systems, urban stormwater, and atmospheric nitrogen deposition from industrial and vehicle emissions,” Christopher Glen, VP of Public Affairs for The Fertilizer Institute, told CNN.
High nitrates in water: How widespread is the problem
The EWG analyzed data from nearly 50,000 public water systems collected between 2021 and 2023. The scale of detection surprised even the researchers behind the report, with contamination showing up in systems serving small rural communities and large metropolitan areas alike.
Most of the systems with the highest contamination draw from local groundwater wells, and the majority serve communities of fewer than 1,000 people.
Key findings from the report:
- More than 6,000 community water systems tested at or above 3 mg/L of nitrates, affecting 62.1 million people
- More than 3,200 systems tested at or above 5 mg/L
- About 3 million people, served by 606 water systems, were exposed to nitrates at or above the federal legal limit of 10 mg/L
- 70 systems hit 20 mg/L or higher — double the legal limit — and 21 systems reached 30 mg/L or more
- The highest reading in the country was 50 mg/L, from a small system near Dinuba, California, serving just 31 people
The report also includes a first-of-its-kind interactive map searchable by zip code. It does not cover private well water, which isn’t regulated by the EPA.
Health risks linked to nitrate exposure
Even at low concentrations, nitrates have been linked to a range of serious health problems.
A 2018 review study published in the International Journal of Environmental Research and Public Health connected nitrate exposure to thyroid disease, several cancers — including gastric, kidney, bladder, colon, colorectal and ovarian — as well as preterm births, birth defects and pediatric cancers.
Peer-reviewed research shows health effects at levels as low as 2 to 5 mg/L, well below the federal limit.
The federal safety standard of 10 mg/L was set in 1962 and officially adopted by the EPA in 1991. It has never been updated, despite decades of newer research suggesting harm at much lower concentrations.
That gap between the current legal limit and the levels where researchers are now documenting health effects is one of the central concerns raised by the EWG’s report.
How to remove nitrates from water at home
If you want to know what’s in your tap, start by checking your local water quality using the EWG Tap Water Database, which is searchable by zip code and covers nearly 50,000 public water systems. It shows nitrate levels and other contaminants detected in your area.
You can also compare that data with your local water utility’s annual water quality report.
Knowing the level in your water is only the first step. Figuring out how to get rid of nitrates from water requires the right equipment, and not every filter does the job.
Two types of point-of-use and whole-house water filter systems are effective:
- A reverse osmosis water filter for nitrates, which forces water through a semi-permeable membrane to strip out contaminants
- Ion exchange (IX) filters, which swap nitrate ions for other ions as water passes through
Standard carbon filters — including most basic pitcher filters — do not remove nitrates. Boiling water doesn’t work either, per the PennState Extension. In fact, boiling concentrates nitrates as water evaporates, making the problem worse rather than better.
What private well owners should know
Private well owners face a different set of risks because the EPA does not regulate private wells, and they were not included in the EWG report. That means there’s no public dataset showing what’s in the water coming out of a private well — the only way to know is to test it.
Households relying on wells, particularly in agricultural regions or areas with septic systems, should be especially proactive about regular testing.
Local health departments and certified labs can test well water for nitrates and other contaminants. Owners who find elevated levels can install a point-of-use or whole-house water filtration system, or take steps to address the source of contamination on their property.
This article was created by content specialists using various tools, including AI.
