EPA legal limit
No federal limit
Maximum Contaminant Level
EWG health guideline
6 ppt
Science-based, stricter target
Health effects
PFBS has a short biological half-life (approximately 1–2 months in humans) and does not bioaccumulate to the degree of long-chain PFAS. However, animal studies show thyroid hormone disruption, reproductive effects, and developmental harm at elevated doses. Its ubiquitous presence in the environment and persistence in water make it a significant contributor to total PFAS body burden. EPA issued a Lifetime Health Advisory of 2,000 ppt in 2022.
Where it comes from
Used as a PFOS replacement in carpet treatments, upholstery, food packaging, and firefighting foam. Found in industrial wastewater and downstream from manufacturing sites. Also detected in agricultural areas where PFAS-containing biosolids have been applied.
How it's regulated
No federal EPA MCL. Monitored under UCMR5 (2023–2025). EPA Lifetime Health Advisory: 2,000 ppt (2022), based on thyroid effects — the high value reflects faster excretion compared to long-chain PFAS. EWG health guideline: 6 ppt.
How to filter pfbs
Not all filters address pfbs. Look for independently certified filters — NSF International certification means the removal claim has been independently verified.
Frequently asked questions
What is pfbs?
PFBS is a four-carbon sulfonic acid PFAS used as a direct replacement for PFOS in stain-resistant coatings, paper and packaging, and firefighting foam formulations. It is among the most mobile PFAS in the environment due to its short chain length and high water solubility. Detected under UCMR5 in water systems serving tens of millions of people across the US.
What are the health effects of pfbs?
PFBS has a short biological half-life (approximately 1–2 months in humans) and does not bioaccumulate to the degree of long-chain PFAS. However, animal studies show thyroid hormone disruption, reproductive effects, and developmental harm at elevated doses. Its ubiquitous presence in the environment and persistence in water make it a significant contributor to total PFAS body burden. EPA issued a Lifetime Health Advisory of 2,000 ppt in 2022.
Is pfbs regulated in drinking water?
No federal EPA MCL. Monitored under UCMR5 (2023–2025). EPA Lifetime Health Advisory: 2,000 ppt (2022), based on thyroid effects — the high value reflects faster excretion compared to long-chain PFAS. EWG health guideline: 6 ppt.
Where does pfbs come from?
Used as a PFOS replacement in carpet treatments, upholstery, food packaging, and firefighting foam. Found in industrial wastewater and downstream from manufacturing sites. Also detected in agricultural areas where PFAS-containing biosolids have been applied.
How do I remove pfbs from tap water?
The most effective methods for removing pfbs 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 pfbs in your water?
Enter your ZIP code to see the measured level in your specific utility.