“Forever chemicals” is a common term for PFAS (per- and polyfluoroalkyl substances), a large family of synthetic chemicals used for decades because many of them resist heat, oil, grease, stains, and water.
Those same properties can make many PFAS highly persistent in the environment. PFAS have been detected in drinking water sources, soil, food, wildlife, and people, making them an important water quality issue.
Quick answer: You cannot identify PFAS by taste, smell, or appearance. Start by checking your public water system's PFAS results or using appropriate laboratory testing. If PFAS are present and additional treatment is appropriate, activated carbon, ion exchange, and reverse osmosis are among the technologies EPA identifies for PFAS reduction. Review evidence for the exact PFAS compounds and filter you are considering.
What Are Forever Chemicals?
PFAS are not one chemical. They are a broad family of fluorinated compounds with different properties, uses, environmental behavior, and levels of scientific study. The nickname “forever chemicals” describes the exceptional environmental persistence of many PFAS; it does not mean every PFAS behaves identically.
PFAS Commonly Discussed in Drinking Water
- PFOA and PFOS: two of the most studied PFAS and the subjects of federal drinking-water limits.
- PFHxS and PFNA: additional PFAS receiving substantial regulatory and scientific attention.
- HFPO-DA (GenX chemicals): processing-aid chemistry developed as an alternative to PFOA in some applications.
- PFBS: a shorter-chain PFAS included in federal risk and regulatory discussions.
Why Are PFAS a Concern?
Exposure can occur through drinking water, food, consumer products, and occupational or environmental pathways. EPA's current review says exposure to certain PFAS at certain levels may be associated with reproductive and developmental effects, immune effects, hormonal interference, increased cholesterol, and an increased risk of some cancers. Research is continuing, and the evidence is not identical for every PFAS.
Keep the risk in perspective: PFAS is a large chemical family. Decisions are best based on the compounds and concentrations actually measured in your water, as well as current public health guidance.
How Do Forever Chemicals Get Into Water?
PFAS can reach groundwater, rivers, reservoirs, and other water sources through industrial releases, wastewater, landfills, PFAS-containing firefighting foams, and disposal of PFAS-containing products. Sites near manufacturing facilities, airports, military installations, firefighting training areas, and certain waste facilities have received particular attention.
For a homeowner, however, the key question is which PFAS have actually been measured in your water and at what concentration.
Current U.S. PFAS Drinking Water Regulation
EPA established enforceable federal drinking-water limits for PFOA and PFOS at 4.0 parts per trillion (ppt) each in 2024. In May 2026, EPA proposed retaining those limits while creating an option for qualifying public water systems to request two additional years—potentially through 2031—to comply. The extension would not be automatic.
EPA separately proposed rescinding the federal regulatory determinations and drinking-water regulations for PFHxS, PFNA, HFPO-DA (GenX), and the Hazard Index mixture involving those three PFAS plus PFBS. The public-comment periods closed in July 2026. As of September 2026, these remain proposed changes rather than final revisions.
PFAS regulation is changing. Check current EPA and state guidance when making decisions based on a regulatory threshold.
How to Find Out Whether PFAS Are in Your Water
Public Water
Start with your water utility. Review its Consumer Confidence Report, ask for PFAS monitoring results, and use state or EPA PFAS monitoring resources if you need more detail.
Private Wells
Private wells are not regulated like public systems under the federal Safe Drinking Water Act. If PFAS are a concern, work with your state or local environmental or health agency and use an appropriate laboratory method. A simple household test strip is not equivalent to laboratory PFAS analysis.
How to Reduce PFAS in Drinking Water
EPA identifies granular activated carbon (GAC), ion exchange, and reverse osmosis among technologies that can effectively reduce PFAS. Performance depends on the particular PFAS, filter design, media, flow, source-water chemistry, maintenance, and service life.
| Technology | Strength | Consideration |
|---|---|---|
| Activated carbon | Well studied for PFAS adsorption | Longer-chain PFAS such as PFOA/PFOS generally adsorb more readily than some shorter-chain PFAS. |
| Ion exchange | Can have high capacity for many PFAS | Media selection and replacement matter. |
| Reverse osmosis | High-pressure membranes can reduce a broad range of PFAS | Requires maintenance and creates a concentrate/waste stream. |
EPA recommends looking for independently certified household filters with applicable PFAS reduction claims, including relevant claims under NSF/ANSI 53 or NSF/ANSI 58. EPA also cautions that existing certification criteria do not necessarily demonstrate treatment down to its newer federal PFAS limits.
Can Black Berkey® and Phoenix Gravity Filters Reduce PFAS?
Yes. Both filter-element families have laboratory evidence of PFAS reduction, although the test programs differ.
- Black Berkey® Elements: Envirotek directly challenged PFOA at 1.00 µg/L (1,000 ppt). Effluent remained below 0.002 µg/L (2 ppt) at the start, 10 gallons, and 25 gallons, reported as >99.9% PFOA reduction. The same report lists PFOS, PFBS, PFDA, PFHxA, PFNA and other fluorinated compounds using PFOA as a surrogate.
- Phoenix Gravity Elements: newer independent testing directly evaluated PFOA and PFOS through 1,500 liters. PFOA challenged at 0.5 µg/L and PFOS at 1.0 µg/L were reported below 0.005 µg/L at every listed checkpoint. Additional Phoenix testing covers PFBS, PFDA, PFHpA, PFHxS and PFNA.
If your Berkey® currently uses Black Berkey® Elements, the existing elements have their own PFAS-reduction evidence. When replacement is eventually needed, Phoenix Gravity is the current compatible primary replacement option and has its own current PFAS test documentation.
Compare the Berkey® PFAS test results before choosing or replacing an element.
Independent PFAS testing is not the same as NSF PFAS certification. The Black Berkey® and Phoenix results described above are element-specific independent laboratory evidence. Current Phoenix NSF/ANSI 42 listings address chlorine and taste-and-odor performance, not PFAS reduction.
Other Ways to Reduce PFAS Exposure
- Check local drinking-water results before deciding whether a filter is useful.
- Maintain and replace filters according to their instructions.
- Follow local fish-consumption or environmental advisories where applicable.
- When practical, look for consumer products that manufacturers identify as made without intentionally added PFAS.
Bottom Line
PFAS cannot be judged by the appearance, taste, or smell of water. The practical sequence is: determine what has been measured, understand the concentration, and choose the treatment based on evidence specific to the PFAS and filter.
For Berkey® owners, both Black Berkey® Elements and Phoenix Gravity elements have PFAS-reduction evidence. Existing Black Berkey® users can review the Black-specific PFOA evidence, while Phoenix provides newer direct PFOA and PFOS testing through 1,500 liters, along with additional PFAS results. When replacement is needed, Phoenix Gravity is the current compatible primary replacement option for many Berkey® systems.