PFHxS (Perfluorohexane sulfonic acid)
PFAS ("forever chemical")
Firefighting foam (AFFF), industrial discharge, consumer product coatings.
EPA regulatory status
Legal limit (MCL)
10 ppt
Goal (MCLG)
10 ppt
MCL 10 ppt (ng/L), finalized April 2024. MCLG = 10 ppt. Also regulated within the PFAS Hazard Index. EPA's May 2025 plan PROPOSES to RESCIND the individual PFHxS regulation (and re-evaluate later); the proposal is not final, so the 2024 rule remains in force as of this data vintage.
Health effects
Linked to thyroid effects, liver effects, immune suppression, and developmental effects. A persistent 'forever chemical.'
This is general public-health information, not medical advice — consult your physician with any health concerns.
National violations
0
EPA's enforcement data (SDWIS/ECHO) records zero violations of PFHxS (Perfluorohexane sulfonic acid)'s rule nationally. See this contaminant's regulatory status above for its current standard and compliance timeline — a zero count is not necessarily an all-clear.
How to remove PFHxS (Perfluorohexane sulfonic acid)
anion exchange
NSF/ANSI 53
Frequently asked questions
What is PFHxS (Perfluorohexane sulfonic acid)?
PFHxS (Perfluorohexane sulfonic acid) is a PFAS ("forever chemical") regulated in US drinking water. Firefighting foam (AFFF), industrial discharge, consumer product coatings.
What is the legal limit for PFHxS (Perfluorohexane sulfonic acid) in drinking water?
MCL 10 ppt (ng/L), finalized April 2024. MCLG = 10 ppt. Also regulated within the PFAS Hazard Index. EPA's May 2025 plan PROPOSES to RESCIND the individual PFHxS regulation (and re-evaluate later); the proposal is not final, so the 2024 rule remains in force as of this data vintage.
What health effects does PFHxS (Perfluorohexane sulfonic acid) have?
Linked to thyroid effects, liver effects, immune suppression, and developmental effects. A persistent 'forever chemical.'
How many violations of PFHxS (Perfluorohexane sulfonic acid) limits are on record nationally?
EPA's enforcement data (SDWIS/ECHO) records zero violations of PFHxS (Perfluorohexane sulfonic acid)'s rule nationally. See this contaminant's regulatory status above for its current standard and compliance timeline — a zero count is not necessarily an all-clear.
How do I remove PFHxS (Perfluorohexane sulfonic acid) from my water?
Filter technologies certified to reduce PFHxS (Perfluorohexane sulfonic acid) include: reverse osmosis (NSF/ANSI 58), activated carbon (NSF/ANSI 53), anion exchange (NSF/ANSI 53). Look for a filter independently certified against the specific NSF/ANSI standard for this contaminant — general "reduces contaminants" marketing claims are not the same as a contaminant-specific certification.
Source: EPA National Primary Drinking Water Regulations · Data as of 2026-07-16