State Hub
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
51–75 of 569North City Water District
WA5339600 · 32,847 served
City of Moses Lake
WA5356300 · 32,428 served
Spanaway Water Company
WA5382850 · 31,908 served
Camas Municipal Water Sewer System
WA5310800 · 31,794 served
Mukilteo Water & Wastewater Distr
WA5357550 · 31,437 served
City of Pullman Water Department
WA5369880 · 31,315 served
City of Mercer Island
WA5353640 · 31,057 served
City of Battle Ground Water Dept
WA5304700 · 30,237 served
Parkland Light & Water Company
WA5366200 · 29,595 served
Fife Dept of Public Works
WA5325050 · 29,091 served
West Sound Utility District #1
WA5302600 · 28,930 served
Cedar River Water & Sewer District
WA5341800 · 28,671 served
Centralia Public Works - Water
WA5312200 · 28,164 served
City of Port Angeles
WA5368550 · 28,067 served
Whitworth Water District 2
WA5396601 · 26,883 served
East Wenatchee Water District
WA5321800 · 26,519 served
City of Mountlake Terrace
WA5357250 · 26,402 served
Cross Valley Water District
WA5316270 · 24,695 served
Vera Water & Power
WA5391450 · 24,692 served
North Perry Ave Water District
WA5360950 · 24,402 served
Lake Meridian Water District
WA5341900 · 24,231 served
City of Oak Harbor
WA5362650 · 23,767 served
Monroe Water System
WA5355820 · 23,467 served
Enumclaw Water Department
WA5323600 · 23,276 served
City of Anacortes
WA5302200 · 22,995 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
Quick Links
Data source: Utility data from EPA SDWIS. 569 active community water systems ingested. CCR contaminant data ingestion in progress.
Last updated: 2026-04-18