PFOS · California

PFOS in California water

PFOS was detected in 100 of 398 California cities with a published result, 99 of them above the federal limit.

Check PFOS where I live All California water

Where PFOS is found in California

99 cities above the federal limit

Cities where detected · above the federal limit first

Not detected or no usable result: 298 cities

Values are from the published EPA record; a contaminant that was never tested is shown as pending, never as a pass. A system-level result, not a measurement of any single home.

Treatment, if a finding establishes a need

What can carry a PFOS reduction claim

Compare treatments for PFOS

Reverse osmosis
Semi-permeable membrane separation removing dissolved minerals, heavy metals, and persistent fluorinated chemicals down to 0.0001 microns.
Activated carbon (GAC)
Highly porous adsorption media targeting chlorine, disinfection byproducts, volatile organic compounds, and organic chemicals.
Anion exchange
Synthetic polyvalent resin beads that exchange unwanted dissolved ionic contaminants for harmless benchmark ions.

What does not help

Boiling does not remove a dissolved chemical compound and can concentrate it. Many pitcher and refrigerator filters carry no verified claim for a compound like this at all.

Order of operations

A finding establishes the need, the need names the capability, the capability requires a verified certification. No product appears before that sequence completes. Filter Finder →

Check your water

99 cities above the federal limit

What can carry a PFOS reduction claim

Find the water system behind your tap.