Seattle Tap Water Quality: Is It Safe to Drink? (2026 Report)

Seattle, Washington tap water receives a grade of A (91/100), which is considered excellent. Out of 76 contaminants tested, none exceed EPA maximum contaminant levels (MCLs) and 1 exceed health guidelines (MCLGs). While the water meets federal standards, some residents may still choose to use a filter for additional peace of mind.

Of the 76 contaminants tested in Seattle's water supply, the most notable include Lead (90th percentile). No contaminants exceed EPA legal limits. 1 contaminant(s) exceed EPA health goals (MCLGs), which are non-enforceable targets set at levels with no known health risk.

Yes, Seattle has 14 EPA violation(s) on record, with the most recent in 2024. Violation types include Other, MR, TT. 4 of these are health-based violations, which are the most serious category.

Seattle water meets EPA standards, so a filter is not strictly necessary. However, some residents prefer the added security of a water filter. EPA health goals (MCLGs) are stricter than legal limits and are set at levels with zero expected health risk. 1 contaminant(s) exceed these stricter goals.

Seattle's drinking water is sourced from purchased surface water and supplied by SKYWAY WATER & SEWER and 3 other water system(s). The system serves approximately 1,160,460 people. Surface water sources include rivers, lakes, and reservoirs.

Under the Safe Drinking Water Act (SDWA), water utilities are required to regularly test for over 90 contaminants. Testing frequency varies by contaminant — some are tested monthly, others quarterly or annually. Seattle's water systems must report results to the EPA and publish an annual Consumer Confidence Report (CCR). The data on this page reflects the latest available EPA testing data.

Seattle's water quality score of 91/100 earns a grade of A, which is considered excellent. This places Seattle among the better-performing water systems in Washington. Visit our Washington state page to see how all cities in the state compare.

If you have concerns about Seattle's tap water, consider these steps: (1) Request your utility's annual Consumer Confidence Report for detailed local data. (2) Get your water independently tested through a state-certified laboratory. (3) Consider an NSF-certified water filter rated for the contaminants found in your area. (4) Contact your water utility (SKYWAY WATER & SEWER) with specific questions. (5) Report water quality issues to your state drinking water program or the EPA Safe Drinking Water Hotline at 800-426-4791.