Snohomish County, Washington: drinking water report. Snohomish County sits north of Seattle, home to about 830,000 residents.
Snohomish County sits north of Seattle, home to about 830,000 residents. Everett, the county seat, draws from the Sultan River through the Spada Lake reservoir – a protected watershed that produces exceptionally clean source water. Other communities purchase wholesale from Everett, from Seattle's system, or operate independent well systems drawing from glacial aquifers.
Everett's Sultan River source is one of the cleanest municipal water supplies in the Pacific Northwest, requiring minimal treatment. The protected watershed model keeps contaminant levels well below federal limits for most parameters.
PFAS is the exception to the generally positive picture. Paine Field (Snohomish County Airport) in Everett has documented AFFF use, and the former Naval Station Everett (now partially transferred to the Port of Everett) is another potential PFAS source. According to the Washington Department of Ecology, PFAS has been detected in groundwater monitoring wells near both facilities. UCMR5 data shows detections in four public water systems countywide.
Most Snohomish County residents on the Everett system enjoy high-quality water. Groundwater-dependent communities and those near Paine Field face more variable conditions.
Check your water to confirm your source and see current data. For PFAS near known sources, activated carbon or RO filters provide household protection. Our water filter guide details which certifications matter. Pull your detailed report, and visit our Washington page for statewide context.