Washington wastewater permits expiring in 2026
18 NPDES permits · 46 MGD combined average flow
18 publicly owned wastewater treatment plants in Washington hold NPDES permits that expire during 2026, issued by Washington State Department of Ecology. The table lists each plant with its permit number, expiry month, average flow, treatment technology and three-year violation count, in order of expiry.
An NPDES permit runs for five years. To keep discharging, a plant must apply for renewal at least 180 days before the expiry date, and the renewed permit usually arrives with tighter effluent limits, new monitoring requirements or a compliance schedule. That is why the year a permit expires is the year a plant starts budgeting for upgrades: nutrient removal, disinfection, capacity or controls.
| Facility | City | Avg flow (MGD) | NPDES permit | Expires | Violations (3y) |
|---|---|---|---|---|---|
| Three Rivers Regional WWTP | Longview | 17.43 | WA0037788 | Feb 2026 | 0 |
| Big Lake WWTP | Mount Vernon | 0.19 | WA0030597 | Feb 2026 | 0 |
| Lott Wastewater Treatment Plant | Olympia | 12.08 | WAG994545 | Dec 2026 | 0 |
| Lynnwood City Wastewater Treatment Plan | Edmonds | 3.96 | WAG994526 | Dec 2026 | 14 |
| Salmon Creek WWTP | Seattle | 3.03 | WAG994551 | Dec 2026 | 0 |
| Picnic Point Wastewater Treatment Facility | Edmonds | 2.45 | WAG994579 | Dec 2026 | 0 |
| Port Orchard WWTP | Port Orchard | 1.98 | WAG994523 | Dec 2026 | 4 |
| Birch Bay Water And Sewer District WWTP | Blaine | 1.17 | WAG994542 | Dec 2026 | 0 |
| Port Townsend WWTP | Port Townsend | 0.83 | WAG994538 | Dec 2026 | 0 |
| Stanwood STP | Stanwood | 0.67 | WAG994534 | Dec 2026 | 0 |
| Sequim Water Reclamation Facility | Sequim | 0.64 | WAG994556 | Dec 2026 | 7 |
| Bainbridge Island WWTP | Bainbridge Island | 0.63 | WAG994558 | Dec 2026 | 1 |
| Lighthouse Point Water Reclamation Facility | Blaine | 0.42 | WAG994581 | Dec 2026 | 0 |
| Friday Harbor STP | Friday Harbor | 0.4 | WAG994576 | Dec 2026 | 33 |
| Clallam Bay Correction Center STP | Clallam Bay | 0.09 | WAG994541 | Dec 2026 | 0 |
| Sekiu STP | Sekiu | 0.07 | WAG994584 | Dec 2026 | 10 |
| Clallam Bay STP | Clallam Bay | 0.04 | WAG994583 | Dec 2026 | 9 |
| Fisherman Bay STP | Lopez Island | 0.02 | WAG994575 | Dec 2026 | 1 |
Washington permit renewals in 2026: questions
Sources and methodology
Flow, permit and violation figures come from the EPA's ICIS-NPDES discharge monitoring records. Population served comes from the Clean Watersheds Needs Survey 2022. Treatment structures are identified by Klarifi's review of aerial imagery, and capital improvement projects are extracted from published municipal budget documents. Violations are counted over the last three years of monitoring reports.
Data refreshed October 26, 2026.
Wastewater terms: NPDES permit · POTW · Biological nutrient removal · Tertiary treatment · Centrate · Ozonation · all terms
Cite this page
Journalists, researchers and educators are welcome to quote these figures. Please credit Klarifi as the source and link to this page.
Klarifi. “NPDES permits expiring in 2026: Washington wastewater plants.” Updated October 26, 2026. https://klarifi.io/facilities/washington/permits-expiring/2026Need a custom cut of the data for a state, a county or a list of plants? Email info@klarifi.io.