EWG's Tap Water Database



July 2017


PFCs, also known as per- and polyfluorinated substances or PFAS, are a family of chemicals used in hundreds of products – from nonstick pans to stain repellent clothing, wire coatings and firefighting foam. The entire group, numbering over 3,000 synthetic chemicals, is concerning because even at low levels, some of these chemicals may result in serious health effects including cancer, endocrine disruption, accelerated puberty, liver damage, and immune system and thyroid changes. These chemicals are persistent in the environment and they accumulate in people.

Nationwide testing for six PFAS chemicals detected contamination in water served to over 16 million people. Five PFCs are no longer being manufactured in the U.S. due to concerns about their extreme toxicity, but pollution from previous use continues to contaminate drinking water around the country. These include PFOA, formerly used to make Teflon, and PFOS, an ingredient in Scotchgard, and the others PFHPA, PFHXS and PFNA. One perfluorinated chemical, PFBS, is still in use.

EWG has set a health guideline of 1 part per trillion, or ppt – equivalent to 0.001 part per billion, or ppb – for each PFC detected in drinking water based on studies of PFOA and PFOS and the chemical and toxicological similarity of many PFC chemicals.

Legacy of pollution

The most infamous family member, PFOA, is a carcinogen that severely polluted the drinking water near a DuPont manufacturing plant in Parkersburg, W.Va. A decade of studies documenting the health impacts of PFOA linked exposure to testicular and kidney cancer, thyroid disease, ulcerative colitis, high cholesterol, and pregnancy-induced hypertension and preeclampsia. Subsequent studies have linked exposure to endocrine disruption and developmental health impacts, as well as reduced effectiveness of vaccines.

In an initial step toward potential regulation, the EPA recently required drinking water utilities across the country to test for six different PFC chemicals. The results greatly underestimate the extent of contamination because the reporting limits were 10 times higher than could be detected in water and the EPA only required reporting of six PFC chemicals, even though the testing method detected 14 different PFC chemicals.

The EPA recently published a health advisory limit of 70 ppt for the combined concentration of PFOA and PFOS in drinking water but has failed to set a legal limit for any of the PFC chemicals. Vermont set a legal limit of 20 ppt in 2016 after discovering drinking water polluted with the chemicals.

Is there a safe level of PFOA or other PFCs in water?

The short answer is no – you do not want any PFCs in your water.

In our Tap Water Database, we utilized a health guideline of 1 ppt for each of six PFC chemicals for which utilities have tested. The health guideline is based on evidence of reduced effectiveness of vaccines, and the impact of PFOA and PFOS on mammary gland development. This health guideline is below the reporting level that the EPA mandated in its testing, which means for every positive test we indicated, the result was above the health guideline.

There is growing agreement among scientists that this entire class of chemicals is of concern. The EPA's 2016 health advisory is for the combined concentration of both PFOA and PFOS. In 2014, Sweden set a drinking water guidance value based on the sum concentration of seven different PFC compounds. In Denmark, the Ministry of Environment and Food utilized the known health effects from PFOA exposure to set a limit for all PFCs in food packaging materials.

For exposure to PFOA, government scientists in New Jersey and Germany indicate that a safe level in drinking water may be zero based on the widespread exposure already occurring from other sources, such as food. Replacement chemicals for PFOA, PFOS and the other PFCs have scant public toxicity information or water testing data, but the information we do have is troubling. The chemical that DuPont is using to replace PFOA, GenX, has also been linked to cancer in lab animals.

How often are PFCs detected in water?

Drinking water suppliers for at least 16 million people have detected the presence of PFCs, and the drinking water supplies of at least 5 million people have tested above the EPA health advisory level for PFOA and PFOS. In the national testing that occurred between 2013 and 2015, PFOA was the most commonly found contaminant, followed by PFOS. The high reporting limits likely greatly underestimate the extent of PFC contamination.

Does the EPA set a legal limit for PFCs in drinking water?

PFCs in drinking water are not regulated by the federal government. In 2016, EPA changed its non-enforceable health advisories for drinking water contamination by PFOA and PFOS from 400 ppt for each to a combined concentration of 70 ppt. At the state level, Vermont has set a legal limit of 20 ppt for PFOA and New Jersey has proposed limits of 14 ppt for PFOA and 17 ppt for PFNA, another chemical in the family.

How can I protect my family from PFCs?

For home water filtration options, both reverse osmosis and activate carbon filters can reduce or eliminate PFOA and other PFC contaminants. Active carbon filters will be less effective at removing the shorter chain replacement chemicals, but we don't know the extent of water contamination by these replacement chemicals.

The EPA should set an enforceable drinking water limit for PFOA and other PFCs found in drinking water. In 2016 EWG requested the EPA investigate the past production, use and disposal of PFOA and other PFCs to eliminate future contamination of drinking water.

With over 3,000 man-made PFC chemicals in existence, the entire class of chemicals is of major concern. Exposure to these chemicals is not limited to water and may also occur through food and food packaging. EWG recommends reducing exposure to fast food wrappers often coated in PFCs by preparing meals at home, and avoiding the use of paper tableware and microwave popcorn. Read our guide for more tips on avoiding PFCs.


Arlene Blum et al., The Madrid Statement on Poly- and Perfluoroalkyl Substances (PFASs). Green Science Policy Institute, 2014. Republished in Environmental Health Perspectives, May 2015. Available at

Danish Ministry of the Environment, Perfluoroalkylated Substances: PFOA, PFOS and PFOSA Evaluation of Health Hazards and Proposal of a Health Based Quality Criterion for Drinking Water, Soil and Ground Water. Environmental Project No. 1665, 2015. Available at

Danish Veterinary and Food Administration, Ministry of Environment and Food of Denmark, Fluorinated Substances in Paper and Board Food Contact Materials (FCM). 2015.

DuPont GenX, 8(e) Filings with EPA, 2010-2013. Available at See also: Sharon Lerner, New Teflon Toxin Causes Cancer in Lab Animals. The Intercept, 2016. Available at

EWG, Teflon Chemical Harmful at Smallest Doses. 2016. Available at

EWG, Scientist in N.J., Germany Support ‘No Safe Level’ of Teflon Chemical in Drinking Water. 2016. Available at

Laurel Schaider et al., Fluorinated Compounds in U.S. Fast Food Packaging. Environmental Science & Technology Letters, 2017, 4(3). Available at See also: EWG, Many Fast Food Wrappers Still Coated in PFCs, Kin to Carcinogenic Teflon Chemical. 2017. Available at

New Hampshire Department of Environmental Service, In-Home Water Filtration Options for PFCs in Household Drinking Water. 2016. Available at

New Jersey Drinking Water Quality Institute, Health-Based Maximum Contaminant Level Support Document: Perfluorooctanoic Acid(PFOA). 2016. Available at See also: New Jersey Department of Environmental Protection, Draft Technical Support Document: Interim Specific Ground Water Criterion for Perfluorononanoic Acid (PFNA, C9). 2017. Available at

Xindi Hu et al., Detection of Poly- and Perfluoroalkyl Substances (PFASs) in U.S. Drinking Water Linked to Industrial Sites, Military Fire Training Areas, and Wastewater Treatment Plants. Environmental Science & Technology Letters, 2016, 3(10). Available at

Zhanyun Wang et al., A Never-Ending Story of Per- and Polyfluoroalkyl Substances (PFASs)? Environmental Science and Technology, 2017, 51(5). Available at