How many wastewater permits expire in Washington in 2026?

14 NPDES permits held by publicly owned wastewater treatment plants in Washington expire in 2026, covering a combined average flow of 0 MGD. The busiest month is Dec 2026 with 11 expiries.

What happens when an NPDES permit expires?

The plant must have applied for renewal at least 180 days before the expiry date. If the agency has not reissued the permit by then, the old permit is administratively continued and stays enforceable. The reissued permit typically carries updated effluent limits based on the latest water-quality standards, which is what drives upgrade projects.

Which is the largest plant with a permit expiring in Washington in 2026?

Big Lake WWTP in Mount Vernon under permit WA0030597, expiring Feb 2026.

How do I get contacts for the plants on this list?

Every plant links to its profile with flow, technology and compliance data. Verified decision-maker contacts for each plant, and the same list for every state and year, are available in Klarifi with a free trial.

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Washington wastewater permits expiring in 2026

Name: Washington NPDES permits expiring in 2026
Creator: Klarifi
License: https://klarifi.io/terms-of-service

14 NPDES permits · 0 MGD combined average flow

14 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.

All Washington NPDES permits →

Publicly owned wastewater treatment plants in Washington with NPDES permits expiring in 2026, from EPA ICIS-NPDES records. Refreshed on every release.
Facility	City	Avg flow (MGD)	NPDES permit	Expires	Technology	Violations (3y)
Big Lake WWTP	Mount Vernon	—	WA0030597	Feb 2026	Uncovered lagoons	0
Three Rivers Regional WWTP	Longview	—	WA0037788	Feb 2026	Clarifiers	0
Snoqualmie WWTP	Snoqualmie	—	WA0022403	Jun 2026	Clarifiers, Carrousels / oxidation ditches	2
Bainbridge Island WWTP	Bainbridge Island	—	WAG994558	Dec 2026	Clarifiers	1
Birch Bay Water And Sewer District WWTP	Blaine	—	WAG994542	Dec 2026	Clarifiers, Aerated lagoons	0
Clallam Bay Correction Center STP	Clallam Bay	—	WAG994541	Dec 2026	Aerated lagoons	0
Fisherman Bay STP	Lopez Island	—	WAG994575	Dec 2026	Aerated lagoons, Covered lagoons, Uncovered lagoons	1
Lott Wastewater Treatment Plant	Olympia	—	WAG994545	Dec 2026	Clarifiers, Biogas silos	0
Port Orchard WWTP	Port Orchard	—	WAG994523	Dec 2026	Clarifiers, Biogas balloons	4
Port Townsend WWTP	Port Townsend	—	WAG994538	Dec 2026	Clarifiers, Uncovered lagoons, Carrousels / oxidation ditches	0
Salmon Creek WWTP	Seattle	—	WAG994551	Dec 2026	Biogas silos	0
Sekiu STP	Sekiu	—	WAG994584	Dec 2026	Clarifiers	10
Sequim Water Reclamation Facility	Sequim	—	WAG994556	Dec 2026	Clarifiers, Aerated lagoons, Uncovered lagoons, Carrousels / oxidation ditches	7
Stanwood STP	Stanwood	—	WAG994534	Dec 2026	Clarifiers, Aerated lagoons, Uncovered lagoons, Carrousels / oxidation ditches	0

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 September 11, 2026.

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