EPA legal limit
No federal limit
Maximum Contaminant Level
EWG health guideline
No guideline
Science-based, stricter target
Health effects
Toxicological data on PFPeS is limited compared to longer-chain PFAS. Available evidence suggests effects on the thyroid and liver consistent with other PFAS sulfonates. Its five-carbon chain places it between the short-chain PFBS (four-carbon) and the regulated PFHxS (six-carbon) in terms of expected bioaccumulation and potency.
Where it comes from
Industrial use as a processing aid and surfactant, often as a replacement for longer-chain PFAS. Found alongside other short-chain PFAS in contaminated water sources near manufacturing sites and AFFF use areas.
How it's regulated
No federal EPA MCL. No EPA Lifetime Health Advisory established as of 2025. Monitored under UCMR5. No EWG health guideline established due to limited toxicological data.
How to filter pfpes
Not all filters address pfpes. Look for independently certified filters—NSF International certification means the removal claim has been independently verified.
Frequently asked questions
What is pfpes?
PFPeS is a five-carbon sulfonic acid PFAS. It is one of the less-studied short-chain PFAS sulfonates but was included in UCMR5 monitoring due to its detection in US water supplies. It shares structural and environmental properties with PFBS and PFHxS.
What are the health effects of pfpes?
Toxicological data on PFPeS is limited compared to longer-chain PFAS. Available evidence suggests effects on the thyroid and liver consistent with other PFAS sulfonates. Its five-carbon chain places it between the short-chain PFBS (four-carbon) and the regulated PFHxS (six-carbon) in terms of expected bioaccumulation and potency.
Is pfpes regulated in drinking water?
No federal EPA MCL. No EPA Lifetime Health Advisory established as of 2025. Monitored under UCMR5. No EWG health guideline established due to limited toxicological data.
Where does pfpes come from?
Industrial use as a processing aid and surfactant, often as a replacement for longer-chain PFAS. Found alongside other short-chain PFAS in contaminated water sources near manufacturing sites and AFFF use areas.
How do I remove pfpes from tap water?
The most effective methods for removing pfpes are: Reverse osmosis (RO), NSF 58 certified RO system, Activated carbon block filter. Look for NSF-certified systems—independent certification confirms removal claims have been verified.
Is pfpes in your water?
Enter your ZIP code to see the measured level in your specific utility.