EPA legal limit
No federal limit
Maximum Contaminant Level
EWG health guideline
No guideline
Science-based, stricter target
Health effects
NMeFOSAA converts to PFOS via environmental and metabolic pathways. Its health concerns are therefore substantially equivalent to PFOS: thyroid disruption, immune suppression, developmental harm, and potential carcinogenicity. Exposure to NMeFOSAA should be counted toward total PFOS-related body burden when assessing risk.
Where it comes from
Legacy use in 3M Scotchgard and related fluorinated surface protection products. Phased out by 3M in 2002 but present in legacy contamination zones, particularly near historical manufacturing sites and in areas where Scotchgard-type products were heavily used.
How it's regulated
No federal EPA MCL. Not individually regulated under the 2024 PFAS NPDWR. Monitored under UCMR5 as a PFOS precursor. No EWG health guideline established. PFOS itself is regulated at 4 ppt under the 2024 NPDWR.
How to filter nmefosaa
Not all filters address nmefosaa. Look for independently certified filters—NSF International certification means the removal claim has been independently verified.
Frequently asked questions
What is nmefosaa?
NMeFOSAA is a PFOS precursor compound — the N-methyl analogue of NEtFOSAA, also derived from 3M fluorochemical manufacturing processes. Like NEtFOSAA, it degrades to PFOS in the environment and in biological systems. Included in UCMR5 to capture the full scope of PFOS-precursor contamination in US drinking water.
What are the health effects of nmefosaa?
NMeFOSAA converts to PFOS via environmental and metabolic pathways. Its health concerns are therefore substantially equivalent to PFOS: thyroid disruption, immune suppression, developmental harm, and potential carcinogenicity. Exposure to NMeFOSAA should be counted toward total PFOS-related body burden when assessing risk.
Is nmefosaa regulated in drinking water?
No federal EPA MCL. Not individually regulated under the 2024 PFAS NPDWR. Monitored under UCMR5 as a PFOS precursor. No EWG health guideline established. PFOS itself is regulated at 4 ppt under the 2024 NPDWR.
Where does nmefosaa come from?
Legacy use in 3M Scotchgard and related fluorinated surface protection products. Phased out by 3M in 2002 but present in legacy contamination zones, particularly near historical manufacturing sites and in areas where Scotchgard-type products were heavily used.
How do I remove nmefosaa from tap water?
The most effective methods for removing nmefosaa 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 nmefosaa in your water?
Enter your ZIP code to see the measured level in your specific utility.