Most of us assume the water coming from our tap is safe. If it meets government standards, it should be fine, right? Not necessarily.
In all 50 states, millions of homeowners are drinking water that contains contaminants like lead, arsenic, trihalomethanes, and PFAS (fully synthetic chemicals linked to industrial pollution and often called “forever chemicals” because they don’t break down over time).
These substances have been linked to long-term health risks, including cancer, reproductive harm, and neurological issues. While many cities meet federal legal standards, recent data from the Environmental Working Group’s (EWG) Tap Water Database reveals that those legal limits often fall far short of current health recommendations.
This article highlights the cities with the most concerning water quality issues and offers clear, actionable steps you can take to protect your household. Spoiler alert: According to the EWG, legal doesn’t always mean safe.
Key Takeaways
- Some major U.S. cities are seeing contaminant levels that are hundreds and even thousands of times above what health experts recommend.
- Though your water may technically fall within the range of legally permitted levels, it could still pose potential long-term health risks.
- Certified water filtration systems offer an effective line of defense for concerned homeowners.
Top U.S. Cities With Notable Concentrations of Harmful Contaminants
Using data from the EWG Tap Water Database, researchers have identified cities where common drinking water contaminants significantly exceed recommended safety thresholds. These include arsenic, lead, trihalomethanes, and chromium-6, a known carcinogen.
While many of these cities are technically in compliance with EPA regulations, EWG’s health guidelines are based on scientific research. The difference is stark.
According to EWG, some of the most extreme cases are:
- Rio Vista, CA, where arsenic was found at 2,150 times the recommended levels
- Houston, TX, where arsenic and other contaminants were found well above recommended levels
- Spokane, WA, where arsenic exceeded the recommended levels by 797 times
Contaminant Health Implications
The presence of contaminants like arsenic, trihalomethanes, bromodichloromethane, and hexavalent chromium in drinking water raises serious health concerns. While the cities highlighted above exceed the EWG’s health guidelines, most are still considered compliant under potentially outdated federal regulations.
The EWG stresses that legal does not always mean safe, as many of the EPA’s current limits haven’t been updated in decades—and may not reflect today’s best scientific understanding. That’s why its health benchmarks are often far more stringent.
To get a clearer picture of the water quality in your area, consult the EWG Tap Water Database and consider using a certified filtration system to reduce your exposure.
Here’s a breakdown of the most concerning contaminants found in this year’s analysis:
Arsenic: A naturally occurring element that can enter groundwater through industrial runoff or natural deposits. Arsenic has been linked to cancer, heart disease, diabetes, and damage to the nervous system.
Total Trihalomethanes (TTHMs): These are chemical byproducts formed when chlorine or other disinfectants react with organic matter in drinking water. Long-term exposure has been associated with increased risk of bladder and skin cancers, as well as developmental harm to fetuses.
Bromodichloromethane: A specific type of TTHM with more targeted health concerns. Studies suggest it can impact reproductive health and fetal development, even at low levels.
Chromium-6 (Hexavalent Chromium): Best known from the Erin Brockovich case, this industrial chemical has been identified as a potent carcinogen. It’s been linked to liver damage, reproductive toxicity, and increased cancer risk—even at trace concentrations.
Top U.S. Cities With Significant PFAS Contamination Levels
Recent analysis of the EWG’s Tap Water Database reveals concerning levels of PFAS—per- and polyfluoroalkyl substances—in municipal water systems across the country. Often called “forever chemicals,” PFAS are fully synthetic compounds used in nonstick cookware, stain-resistant fabrics, firefighting foams, and countless industrial applications.
The problem? PFAS don’t break down over time. Once they enter the environment—or your body—they tend to stay there. Exposure has been linked to serious health risks, including certain cancers, hormone disruption, immune suppression, and developmental issues.
The table below highlights selected cities with significant PFAS contamination levels in their drinking water:
PFAS Health Implications
PFAS chemicals have been linked to a wide range of health concerns, even when exposure happens at very low levels. These compounds can build up in the body over time and have been associated with increased risk of certain cancers, hormone disruption, reproductive and developmental problems, and a weakened immune system.
Researchers have also found evidence that PFAS exposure may interfere with childhood growth, vaccine response, and cholesterol levels. Because these chemicals persist in both the environment and the human body, reducing your exposure is one of the most important steps you can take to protect your long-term health.
PFAS Regulatory Standards
In April 2024, the Environmental Protection Agency (EPA) finalized new national standards for several PFAS chemicals in drinking water. The new limits are 4 parts per trillion (ppt) for PFOA and PFOS, and 10 ppt for GenX, PFNA, and PFHxS. These are some of the strictest standards in the world, designed to help reduce exposure to these harmful, long-lasting chemicals.
While this is a major step forward for public health, it will take time for many municipal water systems to catch up. To see how your local water measures up, visit the EWG Tap Water Database for up-to-date information.
What Can Homeowners Do About Water Contaminants?
The numbers may be concerning, but there are steps you can take to protect your family and reduce the risks. From staying informed to upgrading your home’s water system, small actions can make a big difference for your health and peace of mind.
Stay Informed
Water quality can change over time, especially as regulations evolve and new data becomes available. Checking the EWG Tap Water Database regularly and reviewing your local utility’s water quality report can help you stay ahead of potential issues in your area. Knowing what’s in your water is the first step in protecting yourself and your loved ones from long-term exposure.
Advocacy
Improving water safety takes more than individual action. Supporting local and national initiatives that aim to regulate PFAS, update outdated legal limits, and fund water infrastructure improvements can help drive lasting change. Whether it’s signing a petition, contacting local officials, or backing science-based policies, your voice matters.
Water Filtration
One of the most effective ways to reduce exposure to harmful contaminants is by installing a certified home water filtration system. Leaf Home’s Reverse Osmosis Water Filtration System is designed to reduce PFAS, arsenic, and other common contaminants, so you can feel confident about the water you drink, cook with, and bathe in, every day.
