PFAS in Washington drinking water

Which PFAS compounds were found in Washington?

The compounds detected most often across Washington systems were: PFBS (43 systems), PFPeA (29 systems), PFOS (29 systems, regulated at 4 ppt), PFHxA (24 systems). Only five PFAS currently carry enforceable federal limits, phased in through 2029 (EPA on PFAS risk). Several of the most commonly detected compounds, including PFPeA and PFBA, have no federal limit at all, which is why a system can be fully compliant and still show detections.

What about lead in Washington?

Across the 112 Washington systems serving 10,000 people or more, the median lead 90th-percentile result is 1.85 ppb. The federal action level is 15 ppb, but that is a trigger for utility action rather than a health threshold: no level of lead exposure is considered safe. Lead almost always enters through service lines and household plumbing rather than the treatment plant, so a low statewide median tells you about the systems, not about your building.

How often do Washington systems break drinking water law?

Across 2,404 active community water systems in Washington, 215 have recorded at least one health-based Safe Drinking Water Act violation since 2020, a rate of 8.9 percent. Those systems serve about 170,797 people. Nationally the equivalent figure is 58.8 million.

A health-based violation means a contaminant exceeded a legal limit or required treatment was not delivered, as distinct from a missed sampling deadline. Small rural systems dominate these counts everywhere: one operator, no treatment budget, and a few hundred customers. Read it as a picture of a state's smallest utilities more than of its cities. Full national analysis.

Is Washington tap water safe to drink?

On the PFAS measure specifically, 27.0 percent of tested Washington systems recorded a detection, against a national picture where about a third of tested systems did. That is a statement about the state, not about your tap: within any state, results vary enormously between systems drawing from different sources. The only figure that describes your water is your own utility's, which is why we would rather send you to look it up than have you act on a state average.

For what these compounds are understood to do in the body, see ATSDR on PFAS health effects. One rule worth carrying: a system with no UCMR 5 record has not been shown to be clean. It has not been tested. We never label an untested system as PFAS-free, and neither should anyone else.

Washington cities we score in detail

Full contaminant breakdowns, with every figure cited: