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Washington Water Quality
569
Utilities in database
9.2M
Residents served
22%
On private wells
2
Key contaminants tracked
Drinking Water in Washington
Washington has 569 community water systems serving approximately 9.2 million residents. Primary water sources include groundwater. The most commonly reported contaminants include disinfection byproducts, lead. 22% of Washington residents rely on private wells. DOH holds primary enforcement authority under the Safe Drinking Water Act.
Utilities in Washington
26–50 of 569City of Bremerton
WA5308200 · 72,951 served
City of Kirkland
WA5342250 · 69,243 served
City of Lynnwood
WA5349270 · 68,204 served
Sno Pud 1 - Lake Stevens
WA5380907 · 67,710 served
Woodinville Water District
WA5341600 · 66,699 served
Silver Lake Water & Sewer District
WA5379250 · 65,033 served
Soos Creek Water & Sewer District
WA5340100 · 64,534 served
Southwood
WA5382844 · 64,155 served
Jblm Lewis
WA5326050 · 62,197 served
Lakewood Water District
WA5345550 · 62,089 served
Covington Water District
WA5341650 · 56,172 served
City of Tumwater
WA5389700 · 51,802 served
Longview Water Department
WA5348100 · 49,111 served
City of Wenatchee
WA5394350 · 43,690 served
Issaquah Water System
WA5336350 · 43,584 served
Bonney Lake Water Department City
WA5307650 · 43,371 served
Walla Walla Water Division
WA5392500 · 42,959 served
City of Puyallup
WA5370050 · 39,100 served
King County Water District #20
WA5338950 · 38,974 served
Nob Hill Water Association
WA5359700 · 38,050 served
Tukwila Water Department
WA5389500 · 36,298 served
Firgrove Mutual Inc
WA5325200 · 36,168 served
Silverdale Water Dist 16
WA5379300 · 35,163 served
City of Edmonds
WA5322500 · 34,065 served
City of Bothell Water
WA5307900 · 33,643 served
Key Contaminant Concerns in Washington
Lead
Lead is a naturally occurring heavy metal that was widely used in plumbing infrastructure until it was banned for new installations in 1986. An estimated 9.2 million lead service lines still connect homes to public water mains across the United States, along with millions of homes with lead solder in their internal plumbing.
DBPs
When utilities add chlorine to water to kill pathogens, it reacts with dissolved organic matter — leaves, algae, soil — to produce disinfection byproducts (DBPs). Over 600 DBPs have been identified. The EPA regulates two groups: total trihalomethanes (TTHMs, including chloroform) and haloacetic acids (HAA5). DBP levels tend to be highest in surface water systems and in warm months when organic matter is elevated.
Washington Water FAQs
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Data source: Utility data from EPA SDWIS. 569 active community water systems ingested. CCR contaminant data ingestion in progress.
Last updated: 2026-04-18