Water quality
Washington water quality
According to the Washington State Department of Health (DOH), public water systems must monitor for select PFAS under state action levels adopted in 2021, and the EPA's 2024 federal PFAS rule adds enforceable limits. The EPA has separately documented widespread nitrate contamination of groundwater in the Lower Yakima Valley linked to agriculture. Conditions vary widely between large surface-water systems and private wells.
Documented considerations
Nitrates
According to the EPA, nitrate contamination is a concern throughout the Lower Yakima Valley; in December 2024 a federal court ordered three dairies to test nearby wells and provide alternative water where nitrate exceeds 10 mg/L.
PFAS
According to Washington DOH, the state adopted action levels for five PFAS in 2021 and is collecting statewide testing results; the EPA's final federal PFAS rule requires initial monitoring before April 2027.
Lead
Lead in drinking water in Washington comes mainly from older service lines and home plumbing; utilities are completing service line inventories under the EPA Lead and Copper Rule.
EPA compliance snapshot
From the EPA ECHO Safe Drinking Water Act database, Washington community water systems carrying one or more violations on record:
Most common violation categories
- Revised Total Coliform Rule (408)
- Nitrate (251)
- TTHM (99)
- Total Haloacetic Acids (HAA5) (96)
- Lead and Copper Rule (67)
- Toluene (48)
Counts are public EPA ECHO figures. 'Health-based' means a system carries at least one health-based violation flag in ECHO. A violation on record is not a statement that current tap water is unsafe; most systems return to compliance. Always check your utility's Consumer Confidence Report for current status. Source: EPA ECHO, retrieved 2026-06-01.
Certified filters for Washington's main concerns
- 7.2AquaTru Classic Countertop RO
A no-plumbing countertop 4-stage RO purifier certified to NSF standards for lead, PFAS, fluoride and arsenic with an efficient drain ratio.
- 7.5Culligan US-EZ-4 Under-Sink
An under-sink filter genuinely IAPMO certified to NSF/ANSI 42, 53 and 401 for lead, cysts, VOCs, mercury and PFOA/PFOS.
- 7.2Aquasana AQ-5200 Under-Sink
Certified for lead and PFAS, cheap per gallon, marketing matches the certified scope.
- 4.9ZeroWater 5-Stage Pitcher (7-Cup)
A five-stage ion-exchange pitcher certified for lead, chromium-6 and PFOA/PFOS - but a short 15-gallon filter makes it costly to run.
- 7.3Brita Elite Pitcher (10-Cup)
A pour-through pitcher whose Elite filter is certified to reduce lead, mercury, cadmium and more, with a long 120-gallon cartridge.
- 6.8Frizzlife SK99 Under-Sink Filter
A direct-connect 3-stage under-sink filter with a 0.5 micron carbon block, IAPMO certified to NSF/ANSI 42 and 53 for chlorine, lead and chloramine.
FAQ
- Is Washington tap water safe?
- According to Washington DOH, most public systems meet federal and state standards. The EPA has documented elevated nitrate in Lower Yakima Valley groundwater, which especially affects private wells, so well owners are advised to test.
- Why is nitrate a concern in the Yakima Valley?
- According to the EPA, agricultural sources have driven nitrate above the 10 mg/L health standard in parts of the Lower Yakima Valley; a 2024 federal court order required nearby dairies to test wells and supply alternative water where levels are exceeded.
- Does Washington regulate PFAS in drinking water?
- Yes. According to Washington DOH, the state set action levels for five PFAS in 2021, and the EPA's 2024 national rule adds enforceable maximum contaminant levels with monitoring required by 2027.
Sources
- Washington DOH - PFAS in Drinking Water
- EPA - Lower Yakima Valley Groundwater
- Washington DOH - PFAS Testing Results Data
Not sure how to read your local report? See our guide on reading a water quality report.