PFOS in Drinking Water
Reference information plus historical EPA compliance records associated with pfos.
EPA Limit (MCL)
4 ppt
EPA Goal (MCLG)
0 ppt
Category
PFAS
Regulatory values are a concise reference, not legal or medical advice. Confirm the current standard and rule-specific details on EPA.gov.
Health Effects
Thyroid disease, immune effects, increased cancer risk
Common Sources
Industrial discharge, firefighting foam (AFFF)
Treatment Considerations for PFOS
Commonly cited treatment approaches include: Reverse osmosis, activated carbon, ion exchange. Choose treatment only after a certified water test identifies the substance and concentration; verify NSF/ANSI certification and consult a qualified local professional when needed.
Frequently Asked Questions
What is PFOS and why can it appear in drinking-water records?
PFOS can be associated with drinking water through: Industrial discharge, firefighting foam (AFFF).
What reference value does this page show?
The summarized EPA Maximum Contaminant Level is 4 ppt. Some substances use action levels or rule-specific thresholds instead, so verify the current EPA standard.
Does a historical violation record mean it is in my tap today?
No. A compliance record may be historical or resolved. Use the latest Consumer Confidence Report or a certified test for current local conditions.