EPA legal limit
No federal limit
Maximum Contaminant Level
EWG health guideline
5 ppt
Science-based, stricter target
Health effects
Short-chain PFAS like PFHxA were initially considered safer than long-chain compounds because they do not bioaccumulate as extensively. Emerging research has revised this view — PFHxA shows kidney and liver effects in animal studies and may affect thyroid function. Its high water solubility and widespread detection make it a significant contributor to total PFAS body burden in the US population.
Where it comes from
Industrial applications as a replacement for PFOA and other long-chain carboxylic PFAS. Found in coatings, firefighting foam formulations, food contact materials, and industrial processing aids. Widespread detection in surface water and groundwater reflects its high water mobility.
How it's regulated
No federal EPA MCL. Not included in the 2024 PFAS NPDWR. Monitored under UCMR5 (2023–2025) as an unregulated contaminant. EWG health guideline: 5 ppt, based on kidney toxicity and a precautionary approach to short-chain PFAS.
How to filter pfhxa
Not all filters address pfhxa. Look for independently certified filters — NSF International certification means the removal claim has been independently verified.
Frequently asked questions
What is pfhxa?
PFHxA is a short-chain, six-carbon carboxylic acid PFAS. It is the most widely detected PFAS compound in US drinking water by population exposure, found in systems serving 111 million people across 44 states under UCMR5 monitoring. It has been used as a replacement for longer-chain PFAS in industrial and consumer applications.
What are the health effects of pfhxa?
Short-chain PFAS like PFHxA were initially considered safer than long-chain compounds because they do not bioaccumulate as extensively. Emerging research has revised this view — PFHxA shows kidney and liver effects in animal studies and may affect thyroid function. Its high water solubility and widespread detection make it a significant contributor to total PFAS body burden in the US population.
Is pfhxa regulated in drinking water?
No federal EPA MCL. Not included in the 2024 PFAS NPDWR. Monitored under UCMR5 (2023–2025) as an unregulated contaminant. EWG health guideline: 5 ppt, based on kidney toxicity and a precautionary approach to short-chain PFAS.
Where does pfhxa come from?
Industrial applications as a replacement for PFOA and other long-chain carboxylic PFAS. Found in coatings, firefighting foam formulations, food contact materials, and industrial processing aids. Widespread detection in surface water and groundwater reflects its high water mobility.
How do I remove pfhxa from tap water?
The most effective methods for removing pfhxa 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 pfhxa in your water?
Enter your ZIP code to see the measured level in your specific utility.