Washington Tap Water Quality
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Overview
Seattle's Cedar and Tolt watersheds and Tacoma's Green River supply are protected mountain sources delivering some of the country's best big-city water; Spokane pumps the prolific Spokane Valley-Rathdrum Prairie aquifer. All major systems comply fully.
Washington's watchpoints: PFAS plumes on the West Plains around Fairchild AFB and Airway Heights (which flushed its system and drilled new wells), legacy agricultural nitrate in the Lower Yakima Valley affecting private wells, and the enormous but tightly monitored Hanford cleanup, whose groundwater plumes are kept from the Columbia and from drinking supplies.
Common Contaminants in Washington
Fairchild AFB-area contamination hit Airway Heights' wells in 2017; state action levels and new federal rules drive testing statewide
Lower Yakima Valley dairy-belt groundwater exceeds limits in many private wells, under a long-running EPA-supervised response
Unfiltered Cedar/Tolt supplies rely on watershed protection, ozone, and UV: monitored intensively
Violations & Compliance
Metro compliance is excellent, and Seattle holds filtration avoidance for the Cedar supply. Violations concentrate among the state's many small systems; Yakima Valley nitrate is the standing private-well inequity.
City Water Reports in Washington
Frequently Asked Questions
Sources & References
The safety rating and guidance on this page draw on the following sources. See our full methodology.
- •US EPA Safe Drinking Water Act regulations
- •EWG Tap Water Database
- •The utility's most recent Consumer Confidence Report (CCR)
- •WHO Guidelines for Drinking-water Quality