Washington Water Report Card: Worst Water Systems
The most contaminated public water systems in Washington, ranked by PFAS levels, lead, and EPA violations from official EPA data.
Quick Answer
Artondale Water System has the highest PFAS in Washington at 153.6 ppt (38x the EPA limit). Davenport Water Division has the highest lead at 44 ppb. The tables below rank the worst systems in each category so you can see how your water compares.
Highest PFAS Levels in Washington
Public water systems in Washington with the highest peak PFAS ("forever chemical") reading in EPA UCMR5 testing (2023-2025). The EPA enforceable limit for PFOA and PFOS is 4 ppt.
| # | Water System | Location | Peak PFAS (ppt) | Compounds | vs 4 ppt limit |
|---|---|---|---|---|---|
| 1 | Artondale Water System | Tacoma · 5,828 served | 153.6 | 8 | 38x |
| 2 | Airway Heights City Of | Airway · 9,489 served | 139.3 | 3 | 35x |
| 3 | Southwood Water System | Tacoma · 64,155 served | 110 | 6 | 28x |
| 4 | Moses Lake City Of | Moses Lake · 32,428 served | 54.1 | 5 | 14x |
| 5 | Quistorff | Tacoma · 1,113 served | 44 | 7 | 11x |
| 6 | Peacock Hill | Tacoma · 7,401 served | 25.6 | 6 | 6x |
| 7 | Woodland City Of | Woodland · 10,640 served | 23.4 | 1 | 6x |
| 8 | Skagit County Pud 1 Judy Res | Mount Vernon · 111,415 served | 21.1 | 1 | 5x |
| 9 | Lacey Water Department | Lacey · 105,178 served | 18.8 | 3 | 5x |
| 10 | Vancouver City Of | Vancouver · 373,047 served | 18.6 | 6 | 5x |
| 11 | Richland City Of | Richland · 106,499 served | 17 | 8 | 4x |
| 12 | Fairchild Air Force Base | Fairchild Afb · 9,544 served | 17 | 2 | 4x |
Highest Lead Levels in Washington
Community water systems in Washington with the highest 90th-percentile lead result under the EPA Lead and Copper Rule. The EPA action level is 15 ppb; there is no safe level of lead for children.
| # | Water System | Location | Lead 90th-pctile (ppb) | vs 15 ppb |
|---|---|---|---|---|
| 1 | Davenport Water Division | Davenport · 1,750 served | 44 | 2.9x over |
| 2 | Stevenson Water Dept | Stevenson · 2,594 served | 36 | 2.4x over |
| 3 | Deer Park City Of | Deer Park · 5,255 served | 28.1 | 1.9x over |
| 4 | Trentwood Irrigation District 3 | Spokane · 4,228 served | 27 | 1.8x over |
| 5 | Ilwaco Water Department City Of | Ilwaco · 2,757 served | 26 | 1.7x over |
| 6 | South Bend Water Department | South Bend · 2,930 served | 23 | 1.5x over |
| 7 | Vera Water & Power | Spokane Valley · 24,692 served | 20.8 | 1.4x over |
| 8 | North Beach Water | Ocean Park · 8,093 served | 20 | 1.3x over |
| 9 | Meadows 690 | Lacey · 3,100 served | 19 | 1.3x over |
| 10 | Vinland | Poulsbo · 4,801 served | 19 | 1.3x over |
| 11 | Meadowmeer | Port Orchard · 1,157 served | 16 | 1.1x over |
| 12 | Ponderosa Community Club Inc | Leavenworth · 1,170 served | 15.8 | 1.1x over |
Most EPA Violations in Washington
Community water systems in Washington with the most health-based EPA Safe Drinking Water Act violations on record. A health-based violation means a contaminant exceeded its federal limit or required treatment was not applied.
| # | Water System | Location | Health-based violations |
|---|---|---|---|
| 1 | Walla Walla Water Division | Walla Walla · 42,959 served | 39 |
| 2 | Tacoma Water Division City Of | Tacoma · 446,170 served | 8 |
| 3 | Badger Mountain Irrigation District | Kennewick · 2,331 served | 7 |
| 4 | Bc Water Co | Kennewick · 1,262 served | 6 |
| 5 | Boston Harbor | Olympia · 1,153 served | 5 |
| 6 | Surfside Homeowners | Ocean Park · 2,687 served | 5 |
| 7 | White Salmon City Of | White Salmon · 4,077 served | 4 |
| 8 | Westport Water Department | Westport · 5,346 served | 4 |
| 9 | Long Beach Water Department | Long Beach · 4,628 served | 4 |
| 10 | Water District 19 | Vashon · 3,723 served | 3 |
| 11 | Raymond Water Department | Raymond · 4,620 served | 3 |
| 12 | Basin City Water Sewer District | Mesa · 1,740 served | 2 |
How This Report Card Is Built
PFAS rankings use EPA UCMR5 monitoring (2023-2025), showing each system's peak detection above the 4 ppt EPA limit. Lead rankings use the EPA Lead and Copper Rule 90th-percentile tap results. Violation counts come from the EPA Safe Drinking Water Information System (SDWIS) and count health-based violations. Lead and violation lists are limited to community water systems serving 1,000 or more people. Figures are the most severe on record and do not necessarily reflect current treated water.
Frequently Asked Questions
What is the most PFAS-contaminated water system in Washington?
In EPA UCMR5 testing (2023-2025), Artondale Water System in Tacoma had the highest recorded PFAS level in Washington at 153.6 ppt - about 38x the EPA's 4 ppt limit for PFOA and PFOS.
Which Washington water system has the highest lead levels?
Davenport Water Division in Davenport had the highest 90th-percentile lead result in Washington under the EPA Lead and Copper Rule at 44 ppb - 2.9x the 15 ppb action level.
Which Washington water system has the most EPA violations?
Walla Walla Water Division in Walla Walla has the most health-based EPA Safe Drinking Water Act violations on record in Washington, with 39 violations.
Where does the Washington water report card data come from?
PFAS figures come from EPA UCMR5 monitoring (2023-2025), lead from the EPA Lead and Copper Rule 90th-percentile tap results, and violations from EPA SDWIS health-based violation records. Figures are the most severe on record and do not necessarily reflect current treated water. Check your exact address at knowyourexposure.com.
What Washington Residents Should Do
- Look up your exact address at knowyourexposure.com for your system's data
- See the full Washington water quality overview
- If your system is listed, a certified filter (reverse osmosis for PFAS, NSF-53 for lead) reduces exposure at the tap. See the best water filters.