People can be exposed to PFAS through the various media, including drinking water, household dust, food packaging, and food. Where PFAS-containing firefighting foams and other industrial sources to the environment have contaminated surface water and groundwater, drinking water may be highly contaminated. PFAS have also been found in household dust, fast food packaging, and food products such as fish from contaminated lakes or rivers.

Our understanding on the impacts of PFAS in drinking water is limited to a handful of specific chemicals at present but is rapidly expanding as EPA and other organizations conduct research on these chemicals. The most studied PFAS are perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS). The U.S. Environmental Protection Agency currently identifies PFOA as “likely to be a carcinogen”, which is a step below a “Carcinogenic” classification on the basis of limited to no human data. PFOS is currently identified to have “suggestive evidence of carcinogenic potential”, a step below PFOA.

The EPA recently published interim lifetime health advisories for PFOA and PFOS which are at levels below what can reliably be measured in drinking water. Final lifetime health advisories were published for two replacement compounds, hexafluoropropylene dimer acid (HFPO-DA or “GenX”) and perfluorobutanesulfonic acid (PFBS). Collectively these health advisories noted that the health effects of PFAS may include cancer, liver effects, immunological effects, decreased birth weights, thyroid disease, decreased fertility, and cardiovascular disease.

Drinking water lifetime health advisories are developed by EPA and intended to provide information on contaminants that can cause human health effects and are known or anticipated to occur in drinking water. EPA has published lifetime health advisories for four PFAS: PFOA at 0.004 parts per trillion (ppt), PFOS at 0.020 ppt, GenX at 10 ppt, and PFBS 2,000 ppt. These lifetime health advisories are developed to indicate the level of these PFAS that can be safely present in drinking water without causing adverse effects to consumers over a lifetime of exposure, including sensitive subpopulations like pregnant mothers, immunocompromised individuals, and children.

EPA develops health advisories by reviewing animal and human health studies to determine the levels of exposure at which individual adverse health effects may occur. EPA will consider strength of the study, how the chemical moves through the body and breaks down, and the applicability of the study to humans. Ultimately, health advisories are reflective of the sensitive health endpoint (i.e., the adverse effect that occurs at the lowest level). For EPA’s recently published lifetime health advisories, the health advisory levels were derived for PFOA and PFOS based on a decreased response in 7-year-old children receiving the tetanus and diphtheria vaccine. The GenX and PFBS health advisory levels were derived based on critical liver effects in mice and observed hypothyroidism in newborn mice, respectively.

Health advisories are structured to indicate the level of the contaminant in drinking water at which the sensitive health effect does not occur and to indicate the broader health effects that may occur at higher levels.

Various PFAS have been detected in drinking water across the United States. Drinking water monitoring for 6 PFAS was required from 2013 to 2015 for many systems. As a result of this testing, many states required monitoring for upwards of 30 PFAS in drinking water. While monitoring has not yet taken place, the EPA is preparing to conduct the largest monitoring program for water systems in the United States to date beginning in 2023, which will cover 29 PFAS at more than 10,000 water systems.

Contact your public water system to learn more about PFAS testing and results that may be available for your drinking water supply.

EPA is currently committed to developing a drinking water regulation for PFOA and PFOS, since these are the two most researched PFAS. EPA is also actively considering including other PFAS as part of this process depending on data availability. Before regulating a contaminant, EPA considers theoretical adverse health effects from the contaminant, the extent of occurrence of the contaminant in drinking water, and whether regulation of the contaminant would present a meaningful opportunity for reducing risks to health. Regulation of additional PFAS will depend on the findings of the ongoing health effects research and drinking water monitoring, which is expected to begin in 2023.

If you get your drinking water from a private well, you should have your water tested by a certified laboratory at least once a year. You can find information on how to sample for PFAS and where to send samples for analysis by contacting your state water laboratory certification officer. Contact information for your state can be found at EPA’s drinking water lab certification page. Additional information about well water testing from EPA is available on its private drinking water well FAQ page.

If you are concerned about PFAS in your drinking water, you may consider purchasing a home treatment device. However, in order to make a well-informed and cost-effective decision, consider:

Checking with your water system or consumer confidence report to learn more about the amount of PFAS in your water.

Identifying a device that has been independently certified to remove PFAS.

NSF International, the Water Quality Association, Underwriters Laboratories and CSA International all certify home treatment products for removal of contaminants. The relevant PFAS removal standard is NSF/ANSI Standards 53 and 58. If you choose to use a home treatment device, it is very important to follow the manufacturer’s operation and maintenance instructions carefully in order to make sure the device works properly.

Bottled water quality can vary. Bottled water in the United States is regulated by the U.S. Food and Drug Administration and is required to meet standards equal to the EPA’s tap water standards. There are also individual state standards. However, in most cases, you must contact the bottled water manufacturer for information about PFAS levels. EPA is currently not recommending bottled water based solely on concentrations of PFAS exceeding the health advisories.