Tapped out: America's drinking water and the health risks hidden behind legal limits

Access to clean drinking water is a basic human right, yet millions of Americans unknowingly consume water tainted with hazardous contaminants.

EWG’s latest update to the national Tap Water Database -- the most comprehensive resource of its kind -- reveals that drinking water across the U.S. contains hundreds of chemicals, heavy metals and radioactive substances. They’re often at levels exceeding what scientists consider safe, even if the water quality meets outdated federal standards.

For over 30 years, EWG has led the charge in advocating for stricter regulation of chemicals and empowering consumers with vital information to reduce exposure to hazardous contaminants in water. But decades later, U.S. drinking water still often fails to meet health-based guidelines and can still pose risks, despite complying with legal limits.

And hard-won, vital drinking water protections are at risk, including landmark limits on the “forever chemicals” known as PFAS in drinking water finalized last year. The state of American drinking water continues to be perilous, and the need for stricter regulation remains.

Widespread concern about tap water

Gallup polling consistently shows that Americans, regardless of political affiliation, rank drinking water contamination as their top environmental worry.

This concern is echoed by an EWG 2022 survey, where over half of respondents expressed doubts about the safety of their tap water. About 40 percent said they either refuse to drink tap water or feel unable to drink it directly from the faucet. These statistics highlight a profound lack of trust in the safety of drinking water across the country.

Their concerns are well founded.

A groundbreaking 2019 peer-reviewed study by EWG scientists found that the toxic mixture of contaminants in U.S. drinking water could contribute to more than 100,000 cancer cases nationwide. The study was the first to assess the cumulative cancer risk of multiple pollutants in community water systems across the country.

Despite the growing evidence of health harms from drinking water contamination, federal action has been alarmingly slow. In the past 30 years, the Environmental Protection Agency has set only one new maximum contaminant limit for hazardous chemicals in tap water, targeting six PFAS compounds.

Millions of Americans remain exposed to other unregulated contaminants, leaving critical health protections uncertain.

Polluters and water utilities are now urging the new administration to further weaken federal drinking water protections, especially the EPA’s recent rules reducing PFAS and lead in tap water.

In particular, water utilities – monopolies charged with protecting drinking water consumers – are demanding that EPA restrict chemicals and contaminants in our water on a case-by-case basis, not in groups or mixtures. They are also insisting that EPA can only address these risks when they are found in every state.

What’s in U.S. tap water

EWG’s latest analysis includes water quality data from nearly 50,000 water systems collected between 2021 and 2023. It identified 324 contaminants in drinking water across the country, with almost all community water systems having detectable contaminants.

While some of these pollutants exceed federal legal limits, most contaminants are detected in drinking water at levels above stricter health-based standards established by EWG scientists, putting millions of Americans at risk.

Some key findings include:

• PFAS: EPA data reveal that over 143 million people are exposed to PFAS in their drinking water. These toxic chemicals, which accumulate in the body and do not break down in the environment, have been linked to cancer, immune suppression, fetal harm and reduced vaccine effectiveness. PFAS have been detected in nearly every American’s blood, including newborns.
• Volatile organic compounds: VOCs like trichloroethylene or TCE, perchloroethylene and benzene are widespread contaminants linked to industrial pollution and environmental persistence. These chemicals, even at low concentrations, can cause cancer, liver damage and neurological issues. They are found in tap water at levels ranging from parts per trillion to parts per billion.
• Nitrate: Nitrates from farm runoff and wastewater can contaminate drinking water, especially in rural areas. Long-term exposure to high nitrate levels can cause serious health problems, including cancer, thyroid issues and harm to developing babies. Nitrate contamination is particularly dangerous for infants, especially when used in baby formula, as it can lead to life-threatening conditions like methemoglobinemia.
• Heavy metals: Arsenic is a naturally occurring mineral that causes bladder, lung and skin cancer as well as harm to the skin and lungs. Arsenic is found in drinking water in all 50 states
• Hexavalent chromium, or chromium-6, is a carcinogen made infamous by the Erin Brockovich case in California, and is in the drinking water of over 250 million Americans. There is no federal limit for chromium-6, despite its widespread presence and link to cancer and organ damage.
• Disinfection byproducts: Chlorine disinfectants used to treat water can form harmful byproducts linked to cancer and reproductive health issues. These byproducts are consistently found in large water systems serving millions of people.
• Radiological contaminants: Radium and uranium were detected in many water systems, sometimes exceeding EPA limits. Long-term exposure can lead to neurological disorders, developmental delays and organ damage. Radioactive elements like radium and uranium, naturally occurring or released from mining and industrial processes, increase cancer risk due to ionizing radiation.
• Fluoride: While fluoride is added to water for dental health, high levels can cause dental and skeletal fluorosis and may harm children's neurodevelopment. Some communities have seen fluoride concentrations exceed recommended limits.

Regulations versus reality

Gaps in water safety standards exist throughout the U.S.

The EPA sets maximum contaminant levels, or MCLs, for certain chemicals in drinking water, but many of these legal limits are outdated and inadequate for protecting public health. Some MCLs haven’t been updated in decades, even though new scientific evidence shows that even low levels of exposure to certain chemicals can be harmful.

A major flaw in current water safety regulations is the EPA's approach to assessing health risks from individual contaminants, rather than considering the cumulative impact of multiple pollutants. This method doesn’t reflect real-world exposure, where people are often drinking water contaminated with a mixture of harmful substances.

While most water systems comply with the legal federal standards, what is legal is not necessarily safe.

For example, although the EPA recently set new limits for six PFAS chemicals, most other contaminant limits have remained unchanged since the 1990s. They haven’t been updated to account for new findings on the risks of certain pollutants, and it means that drinking water for many Americans could still pose health risks despite complying with federal limits.

To provide a clearer picture of the true risks in drinking water, EWG’s Tap Water Database uses stricter, science-based guidelines that reflect the latest toxicological research – offering a more accurate assessment of how contaminant concentrations compare with health-based standards.

Empowering consumers 

The Tap Water Database is a free, user-friendly tool that helps consumers find out what's in their drinking water, filling the gaps left by federal regulations. By entering a ZIP code, users can access detailed reports on contaminants, health risks and compliance violations in their local water supply.

They can even get tips on which type of filter they might want to consider buying to reduce pollutants in tap water, tailored to the specific contaminants found in their location.

As public health concerns like cancer and environmental pollution grow, the need for real action has never been more urgent. EWG is committed to providing information that empowers individuals to protect themselves and their families from harmful exposures, particularly as efforts to roll back protections intensify.

How to protect yourself 

If a search for your home on the Tap Water Database shows concerning contaminants in your tap water, here are steps you can take to reduce exposure and health risks:

• Invest in a water filter. Choose the right filter for your needs:
  • Carbon filters (pitcher or faucet-mounted) can reduce levels of PFAS, chlorine, lead and some volatile organic compounds.
  • Reverse osmosis systems effectively remove heavy metals, PFAS, and other harmful chemicals from tap water, including those removed by carbon filters. Reverse osmosis filters also remove fluoride.
  • Whole-house filtration protects against contaminants in both drinking and bathing water. However, in most cases it is not needed and there is a risk of bacteria contamination with this type of filter.
• Stay informed and advocate. Contact local water authorities for information on treatment methods and violations. Advocate for stronger federal and state regulations based on the latest health research. For example, 11 states have adopted PFAS standards for tap water, and more are expected to set PFAS standards as the new federal standards come under attack.
• Save bottled water only for emergencies. In the aftermath of a natural disaster like a wildfire, hurricane, or tornado, or in areas with severe contamination, bottled water from a trusted source can be a safer short-term choice. Opt for brands that provide water quality test results.
• Test your water. If you use a private well, consider getting your well tested.

The road ahead

 While safe water ultimately depends on stronger state and federal regulation and infrastructure improvements, consumer awareness can drive change.

The fight for cleaner, safer water continues, and with the right tools, consumers can help shape a future where tap water more closely aligns with the latest health-based standards, not just outdated legal limits. It should not fall on individual consumers to pay for drinking water filters while polluters get a free pass – everyone deserves better quality tap water.

Take control of your water quality today with EWG’s Tap Water Database.