Common PFAS and Drinking Water Terms

On June 15, 2022, the U.S. EPA issued lifetime Health Advisory Levels for four PFAS compounds: GenX, PFAS, PFOA, and PFBS. These advisories are not enforceable standards for drinking water but were issued to provide information to water providers and the public.

CFPUA understands that customers may have questions about what this means for their drinking water. Staff have compiled a helpful glossary of EPA terms related to drinking water standards and advisories.

PFAS levels at the Sweeney Water Treatment Plant:

CFPUA continues to detect multiple PFAS compounds in its regular sampling of raw water from the Cape Fear River. As of October 2022, testing of drinking water treated at the Sweeney Water Treatment Plant shows that PFAS have been reduced to non-detectable levels by new Granular Activated Carbon (GAC) filters at the plant. Click here to learn more about these filters. 

The chart below lays out PFAS test results following the new GAC filters coming online. Results are shown in parts per trillion (ppt):

*Health advisories for PFOA and PFOS are interim advisories. EPA anticipates finalizing these advisories by the end of 2023. The EPA’s recommended reporting limit (see definitions below) is 4.0 ppt.

Health Advisory Level (HAL): Health Advisories are issued by the EPA to provide information on contaminants that can cause human health effects and are known or anticipated to occur in drinking water. EPA's health advisories are non-enforceable and non-regulatory and provide technical information to state agencies and other public health officials on health effects, analytical methods, and treatment technologies associated with drinking water contamination.

Acute Health Advisory: An Acute Health Advisory Level identifies the level at which short-term exposure to a contaminant may produce adverse health effects. EPA has not issued Acute HALs for any PFAS contaminant to date.

Lifetime Health Advisory: A Lifetime Health Advisory Level identifies levels to protect all people, including sensitive populations and life stages, from adverse health effects resulting from exposure throughout their lives to these PFAS in drinking water. The health advisory levels were calculated to offer a margin of protection against adverse health effects. EPA’s lifetime health advisories also take into account other potential sources of exposure to these PFAS beyond drinking water (for example, food, air, consumer products, etc.), which provides an additional layer of protection.

The advisories issued in June 2022 for four PFAS contaminants are lifetime HALs.

Maximum Contaminant Level Goal (MCLG): An MCLG is the level of a contaminant in drinking water below which there is no known or expected risk to health.

Maximum Contaminant Level (MCL): An MCL is the highest level of a contaminant allowed in drinking water. These are enforceable standards that are set as close to the MCLGs as feasible using the best available water treatment technology.

To date, EPA has not set MCLs for any PFAS compound.

Reporting Limit (RL): An RL is the smallest concentration of a chemical that can be accurately reported by a laboratory. If a laboratory is unable to detect a chemical in a sample, it does not necessarily mean that the chemical is absent from the sample altogether; it could be that the chemical concentration in the sample is below the sensitivity of the testing instrument.

The EPA has set RLs of 4 ppt for PFOA and PFOS, 5 ppt for GenX, and 3 ppt for PFBS.

The current, most advanced PFAS testing methods are not able to accurately measure down to the interim HALs for PFOA and PFOS. Data not detected by these methods does not guarantee the level of PFOA or PFOS is below the EPA’s HAL.