Per- and polyfluoroalkyl substances (PFAS)—often called “forever chemicals” because they persist in the environment for decades—have made headlines as contaminants in drinking water across the United States. As a homeowner, understanding what PFAS are, how they get into water, and what you can do about them is the first step toward making informed decisions about your water quality.
What Are PFAS?
PFAS are a large group of human-made chemicals used since the 1940s in a wide range of products: nonstick cookware, stain- and water-resistant fabrics, food packaging, firefighting foam, and certain cosmetics. There are thousands of PFAS compounds, and they break down very slowly in the environment and in the human body. According to the Agency for Toxic Substances and Disease Registry (ATSDR), some PFAS can remain in the body for years, and research has linked prolonged exposure to certain health effects, including impacts on the immune system, liver, and thyroid, as well as some cancers.
Because of their widespread use and persistence, PFAS have been detected in water supplies—both public and private—across the country. They can enter water through industrial discharge, firefighting training areas, landfills, and runoff from treated products.
Federal and State Standards
In April 2024, the U.S. Environmental Protection Agency (EPA) finalized legally enforceable drinking water standards for six PFAS. Public water systems must meet these limits within five years:
- PFOA and PFOS: 4 parts per trillion (ppt) each
- PFNA, PFHxS, PFBS, and GenX: A limit using a “hazard index” that accounts for combined exposure to these four
Four parts per trillion is an extremely low level—equivalent to about four drops in an Olympic-sized swimming pool—reflecting the EPA’s goal of reducing exposure as much as feasible. Some states have set their own limits or guidance values; checking your state health or environment department is important for local context.
How Do I Know If My Water Has PFAS?
If you’re on a public water system: The new EPA rules require public systems to test for PFAS and report results. You can check your utility’s annual Consumer Confidence Report (CCR) or contact them directly for the latest data.
If you have a private well: Public standards do not apply to private wells. Well owners are responsible for testing. The EPA recommends using a state-certified laboratory and asking specifically for PFAS analysis, as not all standard water tests include it. Your state health department can provide a list of certified labs and, in some cases, guidance on when and how to test.
Can Home Water Filters Reduce PFAS?
Yes. Not all filters are designed to reduce PFAS, but several technologies have been shown to be effective when properly certified and maintained.
- Reverse osmosis (RO): Point-of-use RO systems that meet NSF/ANSI 58 (or equivalent) for PFOA/PFOS reduction can significantly reduce these and many other PFAS. RO is one of the most effective at-home options.
- Activated carbon (granular or block): Some carbon filters are certified to reduce PFOA and PFOS under NSF/ANSI 53 or 58. Performance depends on the type of carbon, contact time, and flow rate. Filter replacement on schedule is critical.
- Certification matters: Look for filters certified to NSF/ANSI 58 (RO) or 53 (carbon) with a specific claim for PFOA and/or PFOS reduction. The NSF database and EPA’s list of filters certified to reduce PFAS can help you verify claims.
No filter removes 100% of every contaminant. Choosing a certified system, following the manufacturer’s maintenance schedule, and retesting periodically (especially for well users) are best practices.
Practical Takeaways for Homeowners
- Check your source. If you’re on municipal water, review your CCR and any PFAS updates from your utility. If you have a well, consider testing through a certified lab.
- Choose certified filtration. If you decide to filter at the tap or for the whole home, select systems certified to reduce the PFAS you’re concerned about (e.g., NSF 58 for RO, or NSF 53/58 with PFOA/PFOS reduction).
- Maintain equipment. Replace filters and membranes on the recommended schedule; performance drops when they’re exhausted.
- Stay informed. Regulations and science on PFAS continue to evolve. Your state health or environmental agency is a good source for local advisories and testing guidance.
PFAS in drinking water is a serious and evolving issue, but homeowners have practical options: understanding their water source, testing when appropriate, and using certified filtration where it makes sense. Informed choices—backed by EPA and state standards and third-party certifications—are the foundation of protecting your household’s water quality.