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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
151–175 of 569City of Milton
WA5354950 · 8,078 served
City of Kalama
WA5337550 · 8,020 served
City of Fircrest
WA5325150 · 7,927 served
City of Pacific
WA5365300 · 7,925 served
Model Irrigation Dist #18
WA5355550 · 7,903 served
Tanglewilde Thompson Place 600
WA5304397 · 7,900 served
Stevens Co Pud - Suncrest
WA5385202 · 7,484 served
Buckley Water
WA5309000 · 7,411 served
Peacock Hill
WA5366637 · 7,401 served
City of North Bend
WA5360100 · 7,228 served
Sultan Water Department
WA5384770 · 7,160 served
City of Granite Falls
WA5329050 · 6,926 served
Lake Chelan Reclamation District
WA5343783 · 6,798 served
City of Elma
WA5323100 · 6,638 served
Sallal Water Association Inc
WA5375560 · 6,600 served
Union Gap Water
WA5390250 · 6,433 served
Black Diamond Water Dept
WA5307220 · 6,407 served
City of Blaine
WA5307300 · 6,319 served
Pasadena Park Irr Dist 17
WA5366300 · 6,269 served
City of Prosser
WA5369750 · 6,211 served
City of Montesano
WA5356000 · 6,204 served
Spo Co Water Dist 3 Sys 4
WA5393354 · 6,155 served
Artondale
WA5303160 · 5,828 served
Seven Lakes Water Association
WA5377660 · 5,823 served
Cashmere Water Department
WA5311700 · 5,815 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