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
201–225 of 569City of Goldendale
WA5328450 · 4,314 served
East Spokane Water Dist 1
WA5321650 · 4,285 served
Trentwood Irrigation District 3
WA5389250 · 4,228 served
Suquamish
WA5386400 · 4,203 served
Crystal Mountain Inc
WA5316400 · 4,154 served
Irvin Water District #6
WA5336050 · 4,150 served
Town of Coupeville
WA5315550 · 4,077 served
City of White Salmon
WA5396350 · 4,077 served
Granger Water Department
WA5329000 · 3,993 served
Eatonville Water Dept
WA5322300 · 3,945 served
City of Everson
WA5324200 · 3,893 served
King County Water District 119
WA5341985 · 3,800 served
Spo Co Water Dist 3 Sys 3
WA5393353 · 3,765 served
Grand Mound
WA5307158 · 3,764 served
Parkview Terrace
WA5366215 · 3,730 served
Water District 19
WA5338900 · 3,723 served
Eastsound Water Users Association
WA5322170 · 3,711 served
Lake Cushman System 5
WA5303529 · 3,675 served
Town of Friday Harbor
WA5326595 · 3,543 served
Roosevelt Water Association
WA5374150 · 3,530 served
City of Zillah
WA5399800 · 3,518 served
Town of Naches
WA5358100 · 3,512 served
City of Colfax Water Department
WA5314000 · 3,507 served
City of Winlock
WA5397500 · 3,502 served
Forks Municipal Water Dept
WA5326000 · 3,468 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