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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
101–125 of 569City of Sumner
WA5385120 · 16,438 served
Olympic View Water & Sewer District
WA5363600 · 16,403 served
Summit Water & Supply Co
WA5385050 · 16,109 served
King County Water District #49
WA5339800 · 16,065 served
Coal Creek Utility District
WA5341750 · 15,989 served
Snoqualmie Water
WA5381080 · 15,848 served
Chelan Co Pud 1
WA5312284 · 15,840 served
City of Kelso
WA5338000 · 15,775 served
Port Orchard Water Dept
WA5368900 · 15,355 served
Fruitland Mutual Water Company
WA5326800 · 15,313 served
City of Shelton
WA5378170 · 15,089 served
Quimper
WA5305783 · 14,548 served
Liberty Lake Sewer & Water District
WA5347150 · 14,500 served
City of Sequim
WA5377620 · 14,293 served
City of Stanwood Water Dept
WA5383650 · 13,785 served
City of Bainbridge Island
WA5397650 · 13,491 served
City of Dupont Water System
WA5320500 · 13,141 served
Jblm Mcchord Field
WA5352200 · 13,115 served
Skyway Water & Sewer
WA5338800 · 12,036 served
Beacon Hill Water & Sewer District
WA5315650 · 11,969 served
Naval Base Kitsap at Bremerton
WA5303468 · 11,792 served
Chehalis Water Department
WA5312250 · 11,718 served
Hoquiam Water Department
WA5334350 · 11,456 served
City of Snohomish
WA5380915 · 11,258 served
City of Duvall
WA5320750 · 11,050 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