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
376–400 of 569Carlsborg Lud 10 12 13 14
WA5300307 · 1,349 served
Nooksack Valley Water Association
WA5359850 · 1,343 served
Evergreen Shores
WA5324163 · 1,329 served
City of Oakville
WA5362750 · 1,325 served
Shorecrest Estates Water Co
WA5378620 · 1,321 served
Harrah Water System
WA5331400 · 1,304 served
Grays Harbor Co Water Dist 1
WA5329200 · 1,302 served
Diamond Lake Water & Sewer District
WA5319207 · 1,299 served
City of Palouse Water Dept
WA5365800 · 1,298 served
Carlyon Beach Homeowners
WA5311159 · 1,273 served
Walla Walla University
WA5392470 · 1,273 served
Freeland Water and Sewer District
WA5326450 · 1,264 served
Bc Water Co
WA53AA373 · 1,262 served
Lakeview Park Water Assn
WA5345350 · 1,259 served
Frog Pond
WA5326627 · 1,229 served
Stevens Co Pud - Waitts Lake
WA5391130 · 1,216 served
City of Roy
WA5345027 · 1,214 served
Washington State Corrections-women
WA5369945 · 1,205 served
Keyport Water
WA5338550 · 1,202 served
Community Sewer and Water District
WA5305966 · 1,200 served
Whitworth University
WA5396580 · 1,200 served
Fisherman Bay Water Association
WA5325547 · 1,195 served
Warm Beach Conference Grounds
WA5392950 · 1,190 served
Lewis Co Water Dist #1
WA5347000 · 1,174 served
Ponderosa Community Club Inc
WA5368417 · 1,170 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.
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Data source: Utility data from EPA SDWIS. 569 active community water systems ingested. CCR contaminant data ingestion in progress.
Last updated: 2026-04-18