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Not health advice. Contact your local water utility for concerns.
Data from EPA Water Quality Reports. For official information, contact your water utility or health department.
Water quality scores for 4 cities in Washington
See the top 20 cities with the cleanest, safest drinking water
Complete water quality rankings for every city in Washington
1,600,000 residents
230,000 residents
320,000 residents
280,000 residents
Washington State benefits from abundant rainfall and snowmelt that provides generally high-quality source water. The Seattle area's protected watershed system produces excellent tap water. However, some communities face challenges with naturally occurring contaminants and agricultural impacts in eastern Washington.
Based on our analysis of 4 cities in Washington, the average water quality score is 95/100. The highest-rated city is Vancouver with a score of 95/100, while Seattle has the most room for improvement at 95/100.
Seattle's water comes from the protected Cedar and Tolt River watersheds in the Cascade Mountains. Other Puget Sound communities draw from rivers and reservoirs. Eastern Washington relies more heavily on groundwater and agricultural area surface water. Groundwater quality varies significantly by region.
These contaminants have been detected in various Washington water systems
Washington State Department of Health manages drinking water programs. The state has established notification requirements for PFAS and other emerging contaminants. Washington's water quality standards are protective, and the state invests significantly in source water protection.
Western Washington generally enjoys excellent water quality, though older homes may have lead concerns. Eastern Washington agricultural areas should monitor nitrate levels. Some areas have naturally occurring arsenic in groundwater. PFAS contamination has been identified near military bases and airports.
Washington residents in older homes should test for lead. Eastern Washington residents should consider activated carbon filtration for agricultural chemicals and nitrate removal systems if levels are elevated. Seattle area residents enjoy some of the nation's best tap water but should address any lead plumbing in older homes.
Most Washington cities have tap water that meets EPA safety standards. With an average score of 95/100 across 4 cities we analyzed, Washington generally has good water quality. However, water quality varies by location, so check your specific city's report.
The most common water quality concerns in Washington include lead (older infrastructure), nitrates (eastern agricultural areas), arsenic (some groundwater). These contaminants can come from natural sources, industrial activities, or aging infrastructure. Review your city's specific report to see which contaminants affect your area.
Whether you need a water filter depends on your specific location and health concerns. Most Washington cities have water that meets EPA standards, though some residents prefer additional filtration for taste or extra protection. Look for filters certified by NSF/ANSI to remove the specific contaminants found in your area.
Public water systems in Washington are required to provide annual Consumer Confidence Reports (CCRs) to residents. You can usually find your report on your water utility's website, request it by phone, or access it through the EPA's database. Our city-level reports above summarize key information from these official sources.
Lead can be present in Washington water, primarily from older plumbing infrastructure. Homes built before 1986 may have lead pipes or lead solder. While water treatment plants remove lead, it can leach into water from service lines and home plumbing. Check your city's specific report for lead testing data, and consider having your tap water tested if you live in an older home.
PFAS ("forever chemicals") have been detected in water systems across the United States, including in Washington. These chemicals are associated with industrial sites, military bases, and firefighting foam use. The EPA has set new PFAS limits effective 2024. Check individual Washington city reports for PFAS testing results in your area.
Based on our analysis, Vancouver has the highest water quality score in Washington at 95/100 (Grade A+). However, "best" depends on your specific health concerns. View our Best Water Quality in Washington page for a complete ranking.
Public water systems in Washington are required by the EPA to test water regularly. Testing frequency depends on the contaminant: bacteria testing occurs daily to weekly, while chemical contaminants may be tested quarterly or annually. Results are published in annual Consumer Confidence Reports. Our site aggregates this data from EPA's SDWIS database.
Compare water quality across counties and find data for your area