PFOS
For PFOS, regulator is US EPA (National Primary Drinking Water Regulations); limit is 0.0000040; unit is mg/L; limit type is MCL (Maximum Contaminant Level), recorded from its source on 2026-08-06.
- Contaminant
- PFOS verified
- Regulator
- US EPA (National Primary Drinking Water Regulations) our reading
- Limit
- 0.0000040 verified
- Unit
- mg/L
- Limit type
- MCL (Maximum Contaminant Level) our reading
Values marked our reading are our classification of what the source says — the source does not print them in those words. The quote below is the evidence for each one; judge it yourself.
What the source says
PFOS | zero | 0.0000040
— epa.gov, retrieved 2026-08-06
Sources disagree
More than one authority states this, and they do not state the same thing. Both are reproduced with the source each came from — deciding between them is yours, not ours.
Limit
epa.gov says limit is 0.0000040, as of 2026-08-06.
PFOS | zero | 0.0000040
https://www.epa.gov/ground-water-and-drinking-water/national-primary-drinking-water-regulations
epa.gov says limit is 4.0 ppt, as of 2026-08-06.
PFOS | Zero | 4.0 ppt
https://www.epa.gov/sdwa/and-polyfluoroalkyl-substances-pfas
Unit
epa.gov says unit is mg/L, as of 2026-08-06.
PFOS | zero | 0.0000040
https://www.epa.gov/ground-water-and-drinking-water/national-primary-drinking-water-regulations
epa.gov says unit is ppt, as of 2026-08-06.
PFOS | Zero | 4.0 ppt
https://www.epa.gov/sdwa/and-polyfluoroalkyl-substances-pfas