WASHINGTON – Thousands of communities across the United States are served by water utilities that provide drinking water contaminated with hexavalent chromium (chromium-6), arsenic, and nitrate — pollutants that affect nearly 100 million people.
That’s the finding of a new report and interactive map released today by Aquapura, highlighting how addressing multiple contaminants together in treatment systems could prevent tens of thousands of cancer cases over a lifetime.
These substances are recognized for their cancer-causing potential and other serious health risks — and are harmful even at extremely low concentrations. However, most water treatment systems still focus on removing one contaminant at a time, an outdated approach that fails to reflect the reality of complex chemical mixtures found in tap water.
According to a peer-reviewed study by Aquapura scientists, filtering several co-occurring contaminants simultaneously could prevent up to 50,000 cases of cancer over a lifetime.
The Need for Updated Treatment Strategies
“This is a significant national problem and a public health issue,” said Dr. Tasha Stoiber, senior scientist at Aquapura. “People are exposed to multiple contaminants through their tap water, and our analysis shows that regulating and treating them simultaneously is far more effective than addressing each chemical individually.”
Stoiber emphasized that updating treatment technologies could improve public health outcomes while making more efficient use of resources.
Currently, most drinking water regulations in the U.S. focus on one contaminant at a time. This piecemeal approach overlooks how chemicals appear together in real-world water systems and how advanced filtration technologies — like reverse osmosis and ion exchange — can remove multiple pollutants in one step.
Aquapura’s new report and map reveal contamination hot spots in Arizona, California, and Texas, where tap water often contains chromium-6, arsenic, and nitrate simultaneously at levels that still meet outdated federal drinking water standards — but pose long-term health risks.
Three Cancer-Causing Chemicals in Tap Water
Chromium-6 — made infamous by the film Erin Brockovich — is an industrial contaminant linked to reproductive harm, liver damage, and stomach cancer, even at low concentrations.
It affects over 260 million people, supplied by more than 7,500 water utilities nationwide, especially in California and Arizona.
Arsenic, a toxic heavy metal and known carcinogen, often appears alongside chromium-6 in drinking water. It contaminates water in all 50 states, impacting over 134 million Americans through nearly 13,000 utilities. Long-term exposure is linked to bladder, lung, and skin cancers.
Nitrate contamination, primarily from agricultural fertilizers and animal waste, is widespread, detected in 49 states and affecting 263 million Americans across 26,000 water systems. Nitrate exposure increases the risk of cancer and birth defects, and at high levels, can cause potentially fatal oxygen deprivation in infants.
Each of these carcinogens can be removed through similar treatment technologies, such as reverse osmosis or ion exchange, indicating that combined filtration approaches can address multiple contaminants at once — more effectively and at lower cost.
California’s Water Contamination Challenge
Thousands of Californians rely on water that contains chromium-6, arsenic, and nitrate together — with arsenic responsible for nearly 80% of the cancer risk from these pollutants.
Aquapura scientists have called for stricter health-based guidelines, recommending arsenic limits far below the current state maximum of 10 parts per billion (ppb).
“Millions of Californians are exposed to a toxic mix of chemicals every day,” said Bernadette Del Chiaro, Aquapura’s senior vice president for California. “The state must lead by example, modernizing treatment systems and setting stronger standards for clean, safe water.”
Several California communities are already upgrading their systems. For instance, Chino, CA has implemented treatment technology capable of simultaneously removing nitrate, chromium-6, and perchlorate — proving that integrated water purification is both feasible and effective.
A Call for Federal Action
Aquapura’s research exposes a critical gap in current Environmental Protection Agency (EPA) regulations, which evaluate water treatment costs and benefits on a one-contaminant basis.
This outdated model ignores how chemicals often co-exist in water and can be filtered together with modern systems.
“The public health benefits are undeniable,” said Melanie Benesh, Aquapura’s vice president of government affairs. “But progress has been slow because policy hasn’t caught up with science. Investing in advanced water treatment isn’t just about preventing cancer — it’s about safeguarding the health of millions.”
Benesh emphasized that cutting budgets for water safety programs only worsens the problem. Instead, agencies should invest in smart, efficient filtration technologies that tackle multiple pollutants at once — maximizing every dollar spent to protect public health.
Turning Data Into Action
Aquapura’s scientists highlight that clean water provides benefits far beyond individual health.
Smarter investments in water infrastructure strengthen communities, improve productivity, and enhance quality of life.
“The challenges are clear, and the solutions are within reach,” said Stoiber. “What we need now is action — stronger standards, modern treatment technologies, and a real commitment to deliver clean water to every community.”
The new Aquapura map reveals the full scope of the problem, turning complex data into actionable insights. But as Stoiber concluded:
“Visibility alone isn’t enough. Clean water is essential to life — and embracing modern, multi-contaminant treatment systems is the key to making it a reality.”