Study: PFAS in Tap Water Linked to Increased Risk of Cancer - Dr. Axe

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By Joe Boland

March 26, 2025

Per- and polyfluoroalkyl substances (PFAS), commonly known as “forever chemicals,” have become a pervasive environmental and public health concern. Their unique chemical properties, which make them resistant to heat, water and oil, have led to their widespread use in various industrial and consumer products.

However, this same persistence means they do not break down easily, accumulating in the environment and our bodies over time, posing significant health risks. Due to their persistent nature, PFAS have become widespread environmental contaminants, particularly in drinking water sources.

Now, new research published in 2025 has found an alarming link between PFAS in tap water and an increase in the incidence of several different types of cancer.

A study published in the Journal of Exposure Science & Environmental Epidemiology in January 2025 examined the relationship between PFAS levels in U.S. drinking water and county-level cancer incidence from 2016 to 2021. Researchers utilized data from the Surveillance, Epidemiology, and End Results (SEER) Program for cancer incidence and the Unregulated Contaminant Monitoring Rule (UCMR) for PFAS concentrations in public water systems.

Specifically, they analyzed data from UCMR3 (2013-2015) and UCMR5 (2023-2024), which measured various PFAS compounds, including PFOA, PFOS, PFNA, PFHxS, PFHpA, PFBS, PFBA, PFHxA, PFPeA and PFPeS.​

The study found significant associations between PFAS contamination in drinking water and increased incidence of cancers in the digestive, endocrine, oral cavity/pharynx and respiratory systems, with incidence rate ratios (IRRs) ranging from 1.02 to 1.33. Notably, perfluorobutanesulfonic acid (PFBS) showed the strongest association with oral cavity and pharynx cancers (IRR: 1.33).

Sex-specific analyses revealed that in males, PFAS exposure was linked to cancers of the urinary system, brain, leukemia and soft tissues, while in females, associations were observed with thyroid, oral cavity/pharynx and soft tissue cancers. The researchers estimated that PFAS in drinking water could contribute to approximately 4,626 to 6,864 incident cancer cases annually in the U.S., depending on the data set used.​

Beyond cancer, PFAS exposure has been linked to other health issues, including liver damage, immune system disruption, thyroid disease, developmental delays in children and decreased fertility. Their persistence in the environment and bioaccumulative nature make them particularly concerning, as they can remain in the human body for extended periods.​

Studies focused on the effects of PFAS have examined how these chemicals impact human health through methods like:

Findings from these type research studies consistently indicate that PFAS exposure is associated with a range of adverse health effects, including:

These studies reinforce that even low levels of PFAS exposure can have detrimental effects on human health.

Beyond that, the broader dangers of forever chemicals include:

While eliminating PFAS exposure entirely is challenging, individuals can take steps to reduce their risks. To mitigate exposure to forever chemicals, individuals can take several steps:​