20% Have Toxins In Their Tap Water

CLIFF NOTES:

• An EWG report says over 62 million Americans may be exposed to elevated nitrates in tap water based on 2021–2023 public system data.
• Federal nitrate guidelines set in 1962 remain at 10 mg/L, while studies cited in the report associate harms at lower levels like 3–5 mg/L.
• The report names large cities (including Los Angeles, Phoenix, and Philadelphia) and small communities with much higher results, often tied to groundwater well systems.
• Des Moines built a major nitrate removal plant, and an Iowa lawmaker cited a child’s letter describing water as “a health concern.”
• Experts quoted recommend reverse osmosis on the kitchen tap for peace of mind, while EWG warns bottled water is generally less regulated than tap.

Over 62 million Americans—about 1 in 5—may be drinking tap water with nitrate levels linked in studies to health harms, according to a new report from the Environmental Working Group (EWG). The report maps nitrate results from public water systems nationwide and highlights both big cities and small towns where concentrations reach levels researchers associate with cancer risks and birth outcomes.

What happened, and who reported it?

A report released Thursday by the Environmental Working Group (EWG), a nonprofit health advocacy organization, concluded that nitrate contamination in public drinking water may affect tens of millions of people.

EWG researchers analyzed nitrate measurements from 2021 to 2023 and used the organization’s tap water database, which aggregates data from nearly 50,000 public water systems across all 50 states.

What are nitrates, and how do they get into drinking water?

Nitrates are compounds made of nitrogen and oxygen that occur naturally in air, water, soil, and plants. They become a drinking-water problem when rainfall causes nitrogen-rich fertilizers used in agriculture to leach into groundwater, streams, and rivers—then move into public water systems downstream.

EWG’s report describes nitrates as invisible, tasteless, and odorless in water.

Why do nitrates in tap water matter?

The report links low concentrations of nitrates in drinking water to health concerns, including thyroid disease and multiple cancers (gastric, kidney, bladder, and colon), along with preterm births and birth defects.

A key detail: the federal limit is old—and the debate is about lower levels

Federal nitrate safety guidelines were set in 1962 at 10 milligrams per liter and have not been updated, the report says. EWG points to peer-reviewed studies that associate health impacts at 5 mg/L, 3 mg/L, and even 2 mg/L.

What did the analysis find across the United States?

EWG’s report states:

• More than 6,000 community water systems, serving more than 62.1 million people, tested at or above 3 mg/L of nitrates.
• More than 3,200 of those systems tested at or above 5 mg/L, a level the report connects to colorectal and ovarian cancer.
• More than 3 million people, served by 606 water systems, were exposed at or above the legal limit of 10 mg/L.

EWG report author Anne Schechinger, senior director of agriculture and climate research at EWG, described the tool as: “a first-of-its-kind map” and said it is searchable by zip code for nitrates and other contaminants.

The report does not cover private wells

EWG noted the analysis does not include private well water, which is not regulated by the US Environmental Protection Agency.

Which cities and communities were named?

EWG’s report highlighted both large cities and smaller communities.

Large systems cited at or above 3 mg/L

The report says the Los Angeles Department of Water and Power (serving nearly 4 million people) tested at or above 3 mg/L on 255 occasions. Other major cities with more than 1 million residents named for testing at 3 mg/L or above included Phoenix; Philadelphia; Las Vegas; San Jose, California; and Columbus, Ohio.

Extremely high results concentrated in groundwater well systems

EWG reported:

• 70 systems were at or above 20 mg/L (twice the federal limit).
• 21 systems were at 30 mg/L or higher.
• A system serving 31 people near Dinuba, California, tested at 50 mg/L, described as the highest in the nation.

Not all high-exposure communities were tiny. The report states more than half a million people in Fresno, California used tap water with up to 14 mg/L nitrate. It also cited Garden City, Kansas (up to 37 mg/L) and Laverne, California (up to 26 mg/L).

Biologist and chemist Christopher Jones, a former University of Iowa research engineer who monitored water quality, said: “Nearly all of the water systems with extremely high levels are groundwater systems that obtain their water from local wells.” He added: “Having 40 milligrams per liter in groundwater is not unheard of, not at all.” Jones was not involved in the EWG report, and the article notes he is running to be Iowa’s next secretary of agriculture.

Des Moines, Iowa: a case study in cost and consequence

The article describes Des Moines, Iowa as a nitrate hot spot with source-water levels so high the city built one of the largest nitrate removal plants in the world. Operating the system costs more than $10,000 a day, according to the report.

A 13-year-old named Ben wrote to Iowa State Rep. Dr. Austin Baeth about the issue, saying: “I remember when I could drink water from the faucet, but now it is a health concern” and “Please don’t ignore this problem!”

Baeth, an internist, responded to the letter’s impact, saying: “I’ve read Ben’s letter and poem numerous times, and I still get choked up,” and added: “Isn’t it sad children have to worry about water that might be harming their health?”

What does industry say about the source of nitrate pollution?

A spokesperson for The Fertilizer Institute (TFI) told CNN in an email that US farmers doubled corn production over the past three decades with only a slight increase in fertilizer use.

TFI Vice President of Public Affairs Christopher Glen said: “Nitrate is a naturally occurring compound found throughout the environment,” and added that fertilizer is one source among others, including “organic matter mineralization, septic systems, urban stormwater, and atmospheric nitrogen deposition from industrial and vehicle emissions.” Glen said attributing elevated nitrate levels primarily to fertilizer use “oversimplifies a complex issue.”

What can be done—by utilities and by households?

Public water systems that regularly test above 10 mg/L are required to notify residents and take action to clean the water, the article says. Mitigation is expensive, and utilities often pass costs to consumers. Des Moines, for example, spent more than $4 million in 1990 to construct its ion-exchange treatment plant.

Filtration advice cited in the article

Jones said the best consumer choice is a reverse osmosis system, which forces water through a semipermeable membrane that captures up to 99% of contaminants.

He advised focusing filtration at the cold-water kitchen tap for drinking, cooking, and coffee: “There’s no need to put it on the whole house — there’s no risk associated with bathing in high-nitrate water or washing dishes and the like.” He added that refrigerator filters should also be connected to the reverse osmosis system.

Schechinger warned against using bottled water as the default solution: “Don’t turn to bottled water as a solution — it’s less regulated in general than tap water.”

Jones summarized the decision as a “peace-of-mind issue,” saying: “If you know the water coming out of your tap is above 3 milligrams per liter of nitrates and you want peace of mind, then I think a reverse osmosis system on the kitchen cold tap is advisable.”

How reverse osmosis and whole-home conditioning fit this problem

When nitrates in tap water rise, the practical goal is simple: reduce what reaches the glass. A reverse osmosis (RO) system is designed for drinking and cooking water, using a membrane barrier that can remove many dissolved contaminants—matching the article’s advice to treat the kitchen cold tap where ingestion happens most.

A whole-home water conditioner does something different. It improves water quality for daily use—helping with scale and mineral-related problems—but it is not a targeted nitrate solution the way RO is. In homes worried about taste, buildup, and overall water feel, a conditioner can complement an RO system by improving water throughout the house while RO protects the water people consume.

Source: CNN