The EPA’s New Drinking Water Advisory Warns against Lower Levels of PFAS, and May Have Important Future Implications for PFAS Regulation

On June 15th, the United States Environmental Protection Agency (“EPA”) updated its drinking water lifetime Health Advisory Levels to include substantially lower levels of PFOA, PFOS, PFBS, and GenX chemicals.  The updated health advisory levels include:

  • PFOA at 0.004 parts per trillion (ppt),
  • PFOS at 0.02 ppt,
  • PFBS at 2,000 ppt, and
  • GenX Chemicals at 10 ppt.

The Health Advisory Levels are intended to apply only to drinking water, not wastewater.  The Health Advisory Levels are not a mandate, and the information provided by the Advisory is non-enforceable. Instead, the Advisory provides information to drinking water system operators as well as state and federal officials about what level of contaminants may cause negative health effects. However, the EPA notes that the PFOA and PFOS levels are interim, meaning the underlying health effects assessment has not yet been finalized. (The GenX and PFBS numbers are final.) 

Despite being non-enforceable, these Health Advisory Levels could serve as guidance for states as they create or revise drinking water standards and may foreshadow more stringent regulatory standards. Additionally, these levels will likely be referenced in litigation to support allegations that even very low levels of PFAS exposure could cause certain health effects.

How the New Advisory Levels Compare to Past EPA Regulation

The EPA acknowledges that current technology is only capable of reliable detection at or above 4 ppt of PFAS. The Health Advisory Levels are orders of magnitude below this 4ppt minimum laboratory reporting limit. This raises immediate questions about how these standards can be reliably applied. To give some indication of just how small the relevant concentrations are, 0.004 ppt is equivalent to one second in a span of 7,925,000 years, or one drop of water in 5,000 Olympic-size swimming pools.  Not only are the Advisory Levels for PFOA and PFOS notably below the level of detection and quantitation for labs, but they are below the average levels of PFAS already detected in the blood of the general population.  PFAS are ubiquitous in modern society, and it is unclear how the Health Advisory Levels can be applied when ambient exposure levels already exceed those thresholds.  

Potential Future Implications of the New Advisory Levels

By the end of 2022, the EPA plans to release a proposed National Drinking Water Regulation for PFOA and PFOS, but this rulemaking will not be finalized until 2023. EPA has yet to confirm whether future regulation of PFAS will be through an enforceable Maximum Contaminant Level (MCL) or through a prescribed treatment technique.  EPA has advised that it considers the ability to measure and treat a contaminant, as well as costs and benefits, in setting an enforceable standard.  However, the low levels outlined in the non-enforceable Health Advisory, which are well below current measurement techniques, raise concerns as to whether EPA intends to release an enforceable MCL at similar concentrations as the Advisory, which would be challenging to implement and have regulatory compliance consequences.   

Resources Consulted

Drinking-Water Health Advisories for PFOA and PFOS, EPA, (last visited June 21, 2022).

Questions and Answers: Drinking Water Health Advisories for PFOA, PFOS, GenX Chemicals, and PFBS, EPA. (last visited June 21, 2022).