How many wastewater permits expire in Oregon in 2028?

10 NPDES permits held by publicly owned wastewater treatment plants in Oregon expire in 2028, covering a combined average flow of 4 MGD. The busiest month is May 2028 with 2 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 Oregon in 2028?

Hermiston WWTP in Hermiston, treating about 1.48 MGD under permit OR0020761, expiring Jan 2028.

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

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

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Oregon wastewater permits expiring in 2028

Name: Oregon NPDES permits expiring in 2028
Creator: Klarifi
License: https://klarifi.io/terms-of-service

10 NPDES permits · 4 MGD combined average flow

10 publicly owned wastewater treatment plants in Oregon hold NPDES permits that expire during 2028, issued by Oregon Department of Environmental Quality. 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.

Other years:

2026 (9)2027 (19)All Oregon NPDES permits →

Publicly owned wastewater treatment plants in Oregon with NPDES permits expiring in 2028, from EPA ICIS-NPDES records. Refreshed on every release.
Facility	City	Avg flow (MGD)	NPDES permit	Expires	Violations (3y)
Hermiston WWTP	Hermiston	1.48	OR0020761	Jan 2028	0
Union WWTP	Union	0.14	OR0029939	Apr 2028	71
Wallowa STP	Wallowa	0.1	OR0020028	May 2028	6
Parkdale STP	Mount Hood Parkdale	0.06	OR0026018	May 2028	3
Nehalem Bay STP	Nehalem	0.87	OR0023370	Jun 2028	0
Siletz STP	Siletz	0.19	OR0020419	Aug 2028	7
North Powder STP	North Powder	0.05	OR0022403	Sep 2028	23
Sheridan WWTP	Sheridan	—	OR0020648	Sep 2028	19
Junction City STP	Junction City	1.19	OR0026565	Oct 2028	167
Yachats STP	Yachats	0.18	OR0020290	Nov 2028	2

Oregon permit renewals in 2028: 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 · Oxidation ditch · Anaerobic digester · 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 2028: Oregon wastewater plants.” Updated October 26, 2026. https://klarifi.io/facilities/oregon/permits-expiring/2028

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