# PFOA — Drinking water contaminant limits by regulator

For PFOA, 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:** PFOA _(verified: appears in the quote below)_
- **Regulator:** US EPA (National Primary Drinking Water Regulations) _(our reading, not quoted from the source)_
- **Limit:** 0.0000040 _(verified: appears in the quote below)_
- **Unit:** mg/L
- **Limit type:** MCL (Maximum Contaminant Level) _(our reading, not quoted from the source)_

## What the source says

> PFOA | zero | 0.0000040

## 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.

### Limit

epa.gov says limit is **0.0000040**, as of 2026-08-06.

> PFOA | zero | 0.0000040

Source: https://www.epa.gov/ground-water-and-drinking-water/national-primary-drinking-water-regulations

epa.gov says limit is **4.0 parts per trillion (ppt)**, as of 2026-08-06.

> PFOA | Zero | 4.0 parts per trillion (ppt) (also expressed as ng/L)

Source: https://www.epa.gov/sdwa/and-polyfluoroalkyl-substances-pfas


### Unit

epa.gov says unit is **mg/L**, as of 2026-08-06.

> PFOA | zero | 0.0000040

Source: 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.

> PFOA | Zero | 4.0 parts per trillion (ppt) (also expressed as ng/L)

Source: https://www.epa.gov/sdwa/and-polyfluoroalkyl-substances-pfas


## Source

- https://www.epa.gov/ground-water-and-drinking-water/national-primary-drinking-water-regulations
- https://www.epa.gov/sdwa/and-polyfluoroalkyl-substances-pfas

Last verified: 2026-08-06. Review by: 2027-08-06.
Part of [Drinking water contaminant limits by regulator](https://referencesource.org/drinking-water-contaminant-limits/).