What are PFAS and PFOS, and how can they be reduced in drinking water?

PFAS are a large family of persistent manufactured chemicals. PFOS is one specific, widely studied member of that family; PFOA is another. These chemicals were historically associated with products such as stain repellents, including Scotchgard formulations, and processes used to manufacture nonstick coatings such as Teflon.

Depending on the compounds and concentrations detected, reduction methods may include granular activated carbon, specialized ion-exchange resin, or reverse osmosis. Not every filter is designed for PFAS, so equipment should carry a verified PFAS-reduction claim and be maintained as directed. The EPA recommends looking for relevant NSF/ANSI 53 or 58 certifications when selecting a home filter. Review the EPA’s PFAS filter guidance.