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
326–350 of 569Hoodsport
WA5334100 · 1,853 served
Rocky Point Water District 12
WA5302052 · 1,831 served
City of Waitsburg
WA5392250 · 1,817 served
City of Electric City
WA5322850 · 1,812 served
Cosmopolis Water Department
WA5315050 · 1,812 served
Canterwood Water System
WA5305859 · 1,805 served
Moab Irrigation Dist #20
WA5355440 · 1,790 served
Glenhaven Lakes Club
WA5328050 · 1,780 served
Rochester
WA5373300 · 1,762 served
Bingen Water Dept
WA5306900 · 1,758 served
Davenport Water Division
WA5318100 · 1,750 served
Sumas Water Dept
WA5384870 · 1,740 served
Basin City Water Sewer District
WA5304461 · 1,740 served
City of Entiat
WA5323500 · 1,730 served
Ritzville Water Department
WA5372700 · 1,725 served
Clallam Bay Sekiu
WA5313200 · 1,719 served
Indianola Water
WA5335650 · 1,705 served
Evergreen Clallam County Pud 1
WA5324181 · 1,694 served
City of Republic
WA5371900 · 1,673 served
Cathlamet Water Dept
WA5311850 · 1,636 served
Scott Lake
WA5376787 · 1,604 served
River Bend Hoa
WA5372750 · 1,603 served
Carnhope Irrigation District 7
WA5311250 · 1,602 served
La Conner Water Dept
WA5343350 · 1,585 served
Consolidated Irrigation Dist 14
WA5314650 · 1,555 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