PFAS (Per- and Polyfluoroalkyl Substances)
EPA Limit (MCL)
4 ppt (0.000004 mg/L)
Health Goal (MCLG)
Zero (0)
No level is considered safe
Unit of Measure
mg/L
How concentrations are reported
EPA finalized MCLs for PFOA and PFOS at 4 parts per trillion (0.000004 mg/L) in April 2024. Multiple PFAS compounds regulated.
Health Effects
Increased risk of certain cancers, immune system effects, thyroid hormone disruption, high cholesterol, reproductive effects.
The EPA has set the health goal (MCLG) at zero, meaning no level of exposure is considered risk-free.
How It Gets Into Water
Industrial discharges, firefighting foam (AFFF), non-stick cookware coatings, water-resistant fabrics
How to Reduce Exposure
- 1Granular activated carbon (GAC) filters reduce some PFAS compounds
- 2Reverse osmosis systems are most effective against PFAS
- 3Pitcher filters with activated carbon provide some reduction
- 4NSF/ANSI 58 or 62 certified systems offer verified PFAS removal
Always look for NSF/ANSI certified filtration products. Certification means the filter has been independently tested to remove the stated contaminants.
Official EPA Guidance
For authoritative information on PFAS (Per- and Polyfluoroalkyl Substances)in drinking water, visit the EPA's official resource page.
View EPA Guidance ↗