PFAS in Drinking Water: Health Risks of Forever Chemicals and How to Protect Yourself

What Are PFAS and Why Are They Called Forever Chemicals?

PFAS have been manufactured since the 1940s and are used in nonstick cookware, water-repellent clothing, food packaging, firefighting foam (AFFF), and industrial processes. The carbon-fluorine bond is one of the strongest in organic chemistry, which means these chemicals do not break down naturally in the environment. They accumulate in soil, groundwater, and living organisms through a process called bioaccumulation.

The two most studied PFAS compounds are PFOA (perfluorooctanoic acid) and PFOS (perfluorooctane sulfonic acid). Although major manufacturers phased out production of these specific compounds, they remain widespread in the environment and have been replaced by shorter-chain PFAS such as GenX (HFPO-DA), whose long-term health effects are still under investigation. PFAS have been detected in the blood of 98% of Americans tested by the CDC's National Health and Nutrition Examination Survey (NHANES).

In 2023, the US Geological Survey published a landmark study sampling tap water from across the country, finding that approximately 45% of samples contained at least one PFAS compound. Contamination was highest near industrial sites, military bases using AFFF firefighting foam, and wastewater treatment plants. The study underscored the ubiquity of these chemicals in both public water systems and private wells.

What Health Risks Are Linked to PFAS Exposure?

The International Agency for Research on Cancer (IARC) classified PFOA as a Group 1 carcinogen (carcinogenic to humans) and PFOS as a Group 2B possible carcinogen in 2023. Epidemiological studies, including the C8 Health Project involving nearly 70,000 people exposed to PFOA-contaminated water near a DuPont plant in West Virginia, established probable links between PFOA exposure and kidney cancer, testicular cancer, thyroid disease, ulcerative colitis, high cholesterol, and pregnancy-induced hypertension.

PFAS exposure disrupts thyroid hormone regulation by competing with thyroid hormones for transport protein binding sites. Studies published in Environmental Health Perspectives demonstrate that even low-level PFAS exposure reduces antibody response to vaccines, including childhood vaccinations for diphtheria and tetanus. The immunosuppressive effects are particularly concerning for children, whose developing immune systems are more vulnerable.

Reproductive health effects include reduced fertility, increased risk of preeclampsia, and lower birth weight. A 2022 meta-analysis in Environment International found that prenatal PFAS exposure was associated with a 78-gram average reduction in birth weight. PFAS are also endocrine disruptors that can interfere with estrogen and testosterone signaling pathways, contributing to developmental effects in exposed populations.

What Did the EPA's Final PFAS Rule Establish?

The EPA's final rule under the Safe Drinking Water Act established legally enforceable maximum contaminant levels (MCLs) for six PFAS compounds. PFOA and PFOS each received individual MCLs of 4 parts per trillion, which is near the limit of detection with current analytical methods. For four additional PFAS—PFHxS, PFNA, HFPO-DA (GenX), and PFBS—the EPA adopted a hazard index approach where the combined concentration must stay below a threshold of 1.0.

Public water systems have three years to complete initial monitoring and five years to implement treatment solutions if they exceed the limits. The EPA estimated that the rule will affect between 6,000 and 10,000 public water systems and cost approximately $1.5 billion annually to implement. The agency projects the rule will prevent thousands of deaths and reduce tens of thousands of serious PFAS-related illnesses. Federal funding of $9 billion through the Bipartisan Infrastructure Law has been allocated to help communities address PFAS contamination.

For households on private wells, the EPA rule does not apply, so individual testing and treatment are necessary. Homeowners can test their water through certified laboratories using EPA Method 533 or Method 537.1. Effective home treatment options include granular activated carbon (GAC) filters, reverse osmosis systems, and ion exchange filters, all of which have been shown to remove over 90% of PFAS compounds when properly maintained.

How Can You Reduce PFAS Exposure at Home?

The most effective home water filtration for PFAS removal is a point-of-use reverse osmosis (RO) system, which studies by Duke University and NC State University found removes 93–99% of PFAS compounds. Granular activated carbon (GAC) filters, including many pitcher-style filters, can remove 60–95% of longer-chain PFAS like PFOA and PFOS but are less effective against shorter-chain compounds like GenX. Ion exchange resins specifically designed for PFAS are another option, particularly effective for shorter-chain variants.

Beyond water filtration, reducing dietary and consumer product exposure is important. PFAS are found in grease-resistant food packaging such as microwave popcorn bags, fast-food wrappers, and some pizza boxes. Choosing PFAS-free cookware (stainless steel, cast iron, or ceramic), avoiding stain-resistant fabric treatments, and selecting personal care products without fluorinated ingredients (often listed as PTFE or "fluoro" compounds) can reduce overall body burden.

The CDC's Agency for Toxic Substances and Disease Registry (ATSDR) recommends that individuals living near known PFAS contamination sites get their blood tested for PFAS levels and consult with healthcare providers about monitoring thyroid function, cholesterol, and cancer screening. Community-level solutions include upgrading municipal water treatment with GAC or ion exchange systems and advocating for stronger state-level PFAS regulations, as several states including Michigan, New Jersey, and Vermont have enacted PFAS limits even stricter than federal standards.