Filters designed to remove toxic “forever chemicals” from drinking water may also reduce other cancer-linked contaminants, according to a new peer-reviewed study.
Scientists say stronger PFAS regulations could bring wider public health benefits, but potential federal rollbacks could delay those protections for North Carolina families.
The
study, published in ACS ES&T Water by the Environmental Working Group, analyzed 19 utilities nationwide that installed advanced treatment systems such as granular activated carbon, ion exchange or reverse osmosis. Researchers found the upgrades often reduced other harmful chemicals, including trihalomethanes and haloacetic acids — byproducts of chlorine disinfection that have been linked to cancer and reproductive health risks.
“PFAS are never detected alone,” said Varun Subramaniam, a science analyst at EWG. “You can cast your net wide and filter out a lot more than just PFAS, even if that’s the treatment goal.”
Some of North Carolina’s largest utilities are already taking steps to comply with the EPA’s new PFAS drinking water standards and say they expect added benefits from upgrades designed to target multiple contaminants.
Fayetteville’s Public Works Commission, which draws water from the Cape Fear River, plans to begin construction in 2026 on a $116 million granular activated carbon filtration system and expects to complete the project by 2031. “Our pilot program showed broad contaminant removal beyond PFAS,” spokesperson Gavin MacRoberts said.
Raleigh Water currently meets federal PFAS limits using powdered activated carbon and has set aside $170 million in its long-term capital plan for potential future upgrades if standards tighten. Assistant Director Edward Buchan said additional treatment could lower other harmful byproducts as well. “Anytime you add more treatment systems, you have the opportunity to reduce the presence of multiple contaminants,” he said.
Other cancer risks linked to drinking water
In more than 80% of the systems studied, levels of disinfection byproducts declined after PFAS treatment upgrades. These chemicals form when chlorine reacts with organic matter in drinking water. Long-term exposure to some disinfection byproducts, including trihalomethanes and haloacetic acids, has been linked to increased cancer risk and possible liver and reproductive problems, according to the Environmental Protection Agency.
Among the systems that saw decreases, trihalomethanes dropped by an average of 42% and haloacetic acids declined by 50% after utilities installed PFAS-targeted treatment.
Reverse osmosis systems delivered the broadest reductions, removing multiple contaminants including radium, arsenic, chromium, atrazine and industrial solvents like TCE. However, researchers said properly designed and maintained granular activated carbon systems — like those planned in Fayetteville — can also significantly reduce contaminant levels.
Most utilities have not upgraded
Despite the potential benefits, few utilities have installed PFAS-specific treatment. Of nearly 3,700 systems nationwide that detected PFAS, only 2% reported adding advanced filtration.
Sydney Evans, a senior science analyst at EWG, said that shows why federal standards and funding are critical. “Systems are not particularly motivated to install treatment before there’s regulation,” she said.
Subramaniam said smaller and rural systems are especially at risk of being left behind. “Very small systems serving fewer than 500 people are far less likely to install advanced treatment than larger utilities,” he said. “That’s why we need federal support to ensure safe drinking water isn’t dependent on ZIP code.”
What’s next for federal rules
The EPA finalized the first national PFAS drinking water standards in 2024, setting strict limits for several types of the chemicals. But the agency is reviewing potential revisions that could narrow the list of regulated compounds and extend compliance timelines.
Evans warned that any rollback could delay the added protections highlighted in the study. “These standards have huge potential to improve water quality across the country,” she said. “Rolling them back would be a huge step backward for public health.”
