Based on information from state health agencies, testing labs, scientific researchers and water filter companies, the most effective choice for in-home treatment of PFAS-tainted tap water is a reverse osmosis filter, followed by an activated carbon filter—a slightly lower-cost option.
Some of these states have issued recommendations for water filters to remove PFOA and PFOS, including: Guidance and factsheet documents from these states recommend two types of filters for removing PFAS chemicals: activated carbon and reverse osmosis.
However, drinking water can contain other PFAS chemicals, sometimes at higher levels than PFOS and PFOA.
Filter Testing by State Agencies In 2007, the Minnesota Department of Health commissioned testing of home water filters to determine their efficacy in removing PFAS.
Six activated carbon filters and eight reverse osmosis filter types were tested.
These filters that were tested for removal of a dozen PFAS chemicals, including both long-chain and short-chain compounds.
The four reverse osmosis systems also removed between 95 and 99 percent of short-chain compounds.
Only Berkey provided EWG with test data for their carbon filters, which reported removal of nine PFAS chemicals, including PFOA and PFOS, all below the detection limit of 2 ppt.
Reverse osmosis systems remove a wider range of other contaminants from drinking water and their effectiveness can be tested at home using an electrical conductivity meter.
You can also consider an activated carbon filter that will most often provide effective removal.