Skip to main content

Per- and Polyfluoroalkyl Substances (PFAS) in Drinking Water

Per- and polyfluoroalkyl substances (PFAS) are a family of thousands of synthetic compounds that are used in everything from housewares to fire-fighting foam. PFAS persist in the environment and bioaccumulate, and studies have found that 97 percent of people have PFAS in their blood [1].

Used to make products resistant to water, heat, and stains, PFAS are used in industrial applications and found in consumer goods such as clothing, food packaging, cookware, cosmetics, and carpet as well as a fire-fighting foam known as aqueous film-forming foam. People are exposed to PFAS by consuming contaminated water and food, breathing in dust with PFAS, and contact with consumer products that contain PFAS.

Evidence of harmful health effects led to the phasing out of two of the most researched chemicals, perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) in the United States through the US EPA PFOA Stewardship Program [2]. But PFOA and PFOS had already made their way into drinking water, surface water, and groundwater.

Scientific studies show a number of these compounds are linked to human health issues [3]. Some manufacturers in the United States replaced the phased-out chemicals (PFOA and PFOS) with shorter chain PFAS such as GenX, and evidence is emerging that these shorter chain PFAS also persist in the environment and bioaccumulate in people with possible health effects [4], [5], [6], [7]. The majority of PFAS now in use have not been studied [8].

What is the evidence of health effects?

Scientific research shows that PFAS affect the immune, endocrine and metabolic systems [3], [9], [10], [11]; however, the health effects of a majority of the 4,700 compounds are unknown

PFOA, one of the most well-studied PFAS, has been linked to kidney and testicular cancer [12], [13], [14], decreased antibody responses to vaccines [15], liver damage, increased cholesterol levels [14], increased risk of thyroid disease [14], increased risk of decreased fertility, decreases in birth weight [16], and increased risk of pregnancy-induced hypertension and preeclampsia [14], [17].

Recognizing the lack of evidence, federal agencies are funding and conducting research to better understand exposure to additional compounds. The U.S. EPA, Department of Defense, Federal Drug Administration, US Department of Agriculture, National Institutes of Health, the Centers for Disease Control and Prevention (CDC) and Agency for Toxic Substances and Disease Registry (ATSDR) are funding and conducting research on health effects from exposure to PFAS, and remediation and treatment strategies for contaminated water and soil.

How are PFAS regulated in drinking water?

There are not yet any federally enforceable standards for PFAS in drinking water in the United States. The U.S. Environmental Protection Agency (EPA) established a health advisory level for two PFAS - PFOA and PFOS -- at a combined total of 70 parts per trillion in drinking water, but that is not an enforceable regulation. In February 2019, the U.S. EPA issued an Action Plan [18] that outlines next steps for the agency to address PFAS and human health impacts at the federal level.

In the absence of a federal drinking water standard, numerous U.S. states including California, Massachusetts, Minnesota, New Jersey, New Hampshire, North Carolina, and Vermont have adopted or proposed drinking water standards for PFOS, PFOA, and other PFAS (e.g. notification levels, health based guidance or maximum contaminant levels).  Additional states including Connecticut, Michigan, New York, and Wisconsin are considering or are in the process of proposing standards for regulating PFAS levels in drinking water to protect human health.

Additional Resources

U.S. Agency for Toxic Substances and Disease Registry, Toxicological Profile for Perfluoroalkyls

U.S. Environmental Protection Agency, PFAS Action Plan

C8 Science Panel

Interstate Technology Regulatory Council (ITRC), PFAS Fact Sheets


1. Calafat, A. M. et al, "Polyfluoroalkyl Chemicals in the U.S. Population: Data from the National Health and Nutrition Examination Survey (NHANES) 2003–2004 and Comparisons with NHANES 1999–2000," Environmental Health Perspectives, pp. 1596-1602, 2007.

2. "Risk Management for Per- and Polyfluoroalkyl Substances (PFASs) under TSCA," Environmental Protection Agency, 2016. [Online]. Available:

3. Sunderland, E.M. et al, "A review of the pathways of human exposure to poly- and perfluoroalkyl substances (PFASs) and present understanding of health effects," Journal of Exposure Science & Environmental Epidemiology , vol. 29, pp. 131-147, 2019.

4. Kabadi, S. V. et al, "Internal exposure-based pharmacokinetic evaluation of potential for biopersistence of 6:2 fluorotelomer alcohol (FTOH) and its metabolites," Food and Chemical Toxicology, vol. 112, pp. 375-382, 2018.

5. S. C. Gordon, "Toxicological evaluation of ammonium 4,8-dioxa-3H-perfluorononanoate, a new emulsifier to replace ammonium perfluorooctanoate in fluoropolymer manufacturing," Regulatory Toxicology and Pharmacology, vol. 59, no. 1, pp. 64-80, 2011.

6. R. C. Buck, "Toxicology Data for Alternative “Short-Chain” Fluorinated Substances," Molecular and Integrative Toxicology , pp. 451-477, 2015.

7. Wang, Z. et al, "Fluorinated alternatives to long-chain perfluoroalkyl carboxylic acids (PFCAs), perfluoroalkane sulfonic acids (PFSAs) and their potential precursors," Environmental International, vol. 60, pp. 242-248, 2013.

8. R. C. Buck, "Perfluoroalkyl and Polyfluoroalkyl Substances in the Environment: Terminology, Classification, and Origins," Intergrated Environmental Assessment and Management, vol. 7, no. 4, pp. 513-514, 2011.

9. P. N. Breysse, "Toxicological Profile for Perfluoroalkyls," Agency for Toxic Substances & Disease Registry, Atlanta GA, 2018.

10. "THE MADRID STATEMENT," 2015. [Online]. Available:

11. Lewis, R. C. et al, "Serum Biomarkers of Exposure to Perfluoroalkyl Substances in Relation to Serum Testosterone and Measures of Thyroid Function among Adults and Adolescents from NHANES 2011–2012," International Journal of Environmental Research and Public Health, vol. 12, no. 6, pp. 6098-6114, 2015.

12. Barry, V. et al, "Perfluorooctanoic Acid (PFOA) Exposures and Incident Cancers among Adults," Environmental Health perspectives, vol. 121, pp. 1313-1318, 2013.

13. W. Nicole, "PFOA and Cancer in a Highly Exposed Community: New Findings from the C8 Science Panel," Environmental health perspectives, 2013.

14. C. S. Panel, "Probably Link Reports,", Parkersburg, West Virginia, 2012.

15. DeWitt, J. C. et al, "Exposure to per-fluoroalkyl and polyfluoroalkyl substances leads to immunotoxicity: epidemiological and toxicological evidence.," Jounral of Exposure Science & Environmental Epidemiology, vol. 29, pp. 148-156, 2019.

16. Negri, E. et al, "Exposure to PFOA and PFOS and fetal growth: a critical merging of toxicological and epidemiological data.," Critical reviews in Toxicology, vol. 47, no. 6, pp. 489-515, 2017.

17. Wikstrom, S. et al, "Early pregnancy serum levels of perfluoroalkyl substances and risk of preeclampsia in Swedish women.," Scientific Reports, vol. 9, no. 1, 2019.

18. "EPA's PFAS Action Plan," Environmental Protection Agency, 2019. [Online]. Available:

Office of Public Programs | Center for Scientific Evidence in Public Issues

Internet Voting Remains Insecure, Says AAAS EPI Center

Office of Public Programs | Center for Scientific Evidence in Public Issues

Green Stormwater Infrastructure Helps Curb Effects of Climate Change in Cities

Center for Scientific Evidence in Public Issues

Deploying Data-Driven Green Stormwater Infrastructure Programs

Center for Scientific Evidence in Public Issues

EPI Center letter to members of the Ohio House of Representatives regarding internet voting

Center for Scientific Evidence in Public Issues

Video: The Risks of Internet Voting in the Puerto Rico Electoral Code of 2020

Office of Public Programs | Center for Scientific Evidence in Public Issues

Summit Briefs Policy-makers on Drinking Water Safety

Office of Public Programs | Center for Scientific Evidence in Public Issues | COVID-19 Resources

Top State Officials Urged to Bar Security-Flawed Internet Voting Platforms

Center for Scientific Evidence in Public Issues | COVID-19 Resources

Scientific Experts Call on Elected Officials to Avoid Any Internet Voting

Center for Scientific Evidence in Public Issues

Bringing Scientific Evidence to Meet Local Policy Challenges, a Town Hall at the AAAS Annual Meeting