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 the U.S. Environmental Protection Agency (EPA) and other organizations conduct research on these chemicals. The most studied PFAS are perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS). EPA 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.

In June 2022, EPA 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 is not yet complete, EPA began its largest monitoring program for water systems in the United States to date in January 2023. More than 10,000 systems will participate in one year of monitoring for 29 PFAS between 2023 and 2025. Data will not be completed until summer 2026 but preliminary monitoring results will be available quarterly beginning in Summer 2023.

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

On March 14, 2023, EPA proposed the first national primary drinking water standards for six PFAS.

The EPA proposal establishes maximum contaminant levels goals (MCLGs) and maximum contaminant levels (MCLs) for six PFAS. Individual MCLGs and MCLs are proposed for both PFOA and PFOS on the EPA’s determination that these compounds are carcinogenic. An additional MCLG and MCL has been proposed for PFHxS, PFNA, PFBS, and HFPO-DA using a hazard index of 1.0. A hazard index is a tool used to evaluate combined risk from exposure to a mixture of contaminants. It is determined by adding hazard quotients for each PFAS, which are calculating by dividing the concentration of the PFAS by the health-based water concentration (HBWC). The HBWC for each PFAS respectively is 9.0 ppt for PFHxS, 10.0 ppt for GenX and PFNA each, and 2,000.0 ppt for PFBS.

The proposal also includes the following requirements for water systems:

• Initial Monitoring: Large groundwater systems serving greater than 10,000 people and surface water systems will need to complete quarterly monitoring over a 12-month period using either EPA Method 533 or 537.1. Small groundwater systems serving less than 10,000 people will need to complete monitoring twice over a 12-month period. Initial monitoring will need to be complete within 3 years of the final rule. Previous monitoring results from state or national monitoring programs may be used.
• Compliance Monitoring: Water systems will be required to monitor quarterly initially but will be eligible for reduced monitoring if PFAS levels are less than one-third of the MCLs. Compliance will be determined based on a running annual average.
• Public Notification: Water systems will be required to notify the public within 30 days of any PFAS MCL violations. Systems must also report compliance monitoring results as part of their Consumer Confidence Reports.

Small System Compliance Technologies: In addition to the use of GAC, IX, NF, and RO as BATs for water systems, EPA provides for smaller systems serving less than 3,300 people to use point-of-use (POU) RO and NF filters to comply with the rule. It is important to note that POU filters are currently not certified by NSF/ANSI for removal of PFAS to levels below the proposed standards.

The proposal is not yet finalized and is subject to changes based on comments from the public. The EPA intends to finalize the rule the end of 2023 or early 2024.

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.