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
426–450 of 569Bayview Beach Water District
WA5305535 · 1,035 served
Rosario
WA5374270 · 1,031 served
Cape George Colony Club Inc
WA5311050 · 1,022 served
Samish Farms Water Assn
WA5375645 · 1,017 served
Lake Quinault
WA5370350 · 1,003 served
Sunserra at Crescent Bar
WA53AA745 · 1,000 served
Underwood
WA5390200 · 1,000 served
Dockton Water Association
WA5319550 · 992 served
Glacier Springs Water Assn
WA5327750 · 992 served
Amboy Clark Public Utilities
WA5304625 · 991 served
Odessa
WA5363050 · 986 served
Vader-enchanted Valley
WA5390900 · 985 served
The Buttes
WA5308253 · 973 served
Illahee Oyehut
WA5335450 · 971 served
Marion Water Co Inc
WA5351750 · 966 served
Burton Water Cooperative
WA5309800 · 964 served
Yak Co - Buena Water System
WA5334301 · 952 served
Town of Coulee City
WA5315300 · 944 served
Cape Horn Maintenance Company
WA5311060 · 940 served
Lyle Water System
WA5349000 · 938 served
Preston Industrial Park Water Assn
WA5318879 · 930 served
Sunwood Lakes Homeowners Assoc Inc
WA5386304 · 925 served
Long Lake View Est 2 5
WA5348031 · 923 served
Puget Island
WA5369760 · 920 served
Lake Cushman System 3
WA5303528 · 917 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