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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
351–375 of 569City of Mossyrock Public Utility
WA5356350 · 1,553 served
Pole Road Water Association
WA5368350 · 1,545 served
Naval Base Kitsap at Keyport
WA5390520 · 1,540 served
Lake Minterwood
WA5355210 · 1,539 served
Tapps Island Water System
WA5387181 · 1,500 served
Sunland Estates Homeowners Assn
WA5385240 · 1,480 served
Blanchard Edison Water Assn. Inc.
WA5307450 · 1,480 served
City of Tieton Water Dept
WA5388300 · 1,475 served
Graham Hill Mutual Water Co Inc
WA5328650 · 1,474 served
Hogans Corner
WA53AA554 · 1,458 served
Coulee Dam Water Dept
WA5315400 · 1,454 served
Point Roberts Water District No 4
WA5395750 · 1,440 served
City of Grand Coulee Water Dept
WA5328700 · 1,428 served
High Valley Country Club
WA5332700 · 1,425 served
Town of Reardan
WA5371550 · 1,418 served
City of Langley
WA5345950 · 1,416 served
Whatcom County Water Dist #7
WA5395900 · 1,410 served
Chelan Co Pud1 - Peshastin
WA5367050 · 1,397 served
City of Pomeroy
WA5368400 · 1,395 served
Lake Josephine Riviera
WA5343980 · 1,380 served
Sno Pud 1 - May Creek
WA5352105 · 1,374 served
Harbor Hills Community Water System
WA5333860 · 1,373 served
Pelican Point by Cascadia Llc
WA5366800 · 1,357 served
Whatcom County Water Dist #2
WA5395700 · 1,353 served
Town of Winthrop
WA5397750 · 1,350 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