Which water filters reduce PFAS?

Reverse osmosis is the most reliable technique: in the only study done in real homes (Herkert et al., 2020), every under-sink reverse osmosis unit removed more than 94% of PFAS, short chains included. Activated carbon blocks and ion exchange resins work when the exact model is certified to NSF/ANSI 53 for PFOA/PFOS and the cartridge is changed on time; saturated carbon can release what it has captured.

Mostly no. Carbon-only pitchers remove 20 to 70% of PFAS depending on the model, the water and wear. Certified ion exchange pitchers (such as ZeroWater) reach 95 to 100% when new, but the cartridge runs out after a few dozen litres. Look for "PFOA/PFOS" in the certification, not just "NSF".

No. PFAS do not evaporate at 100 °C. Boiling reduces the volume and slightly concentrates the rest. Whole-house carbon filters are not an answer either: in the North Carolina study, four of eight returned water with more PFAS than went in.

That an independent laboratory checked the filter brings water spiked with PFOA/PFOS below the standard's pass mark, over the rated life. That mark is 70 ng/L on data sheets certified before 2019 and 20 ng/L for the current PFAS claim. Both are far above the 4 ng/L legal reference and this site's 0.5 ng/L benchmark. A certification cuts exposure hard; it does not guarantee a precise number at the tap.

"Certified" means a body such as IAPMO R&T or NSF listed the product after its own tests and audits the factory. "Tested" means the manufacturer paid a laboratory (SGS, for example) to measure a sample with the standard's methods, with no official listing. We show both, but not at the same level of proof.

Because below 0.5 ng/L of PFAS-4 no filter is needed for PFAS. Between 0.5 and 4 ng/L, a certified pitcher or carbon block changed on time reduces exposure. Above 4 ng/L, the strictest legal reference in Europe, reverse osmosis is the consistent choice. Look up your commune on the homepage.