Oregon wastewater permits expiring in 2028
10 NPDES permits · 3 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.
| Facility | City | Avg flow (MGD) | NPDES permit | Expires | Technology | Violations (3y) |
|---|---|---|---|---|---|---|
| Hermiston WWTP | Hermiston | 1.56 | OR0020761 | Jan 2028 | Clarifiers, Uncovered lagoons, Biogas silos | 0 |
| Union WWTP | Union | 0.12 | OR0029939 | Apr 2028 | — | 71 |
| Wallowa STP | Wallowa | 0.1 | OR0020028 | May 2028 | Aerated lagoons, Covered lagoons | 6 |
| Parkdale STP | Mount Hood Parkdale | 0.04 | OR0026018 | May 2028 | — | 3 |
| Nehalem Bay STP | Nehalem | 0.3 | OR0023370 | Jun 2028 | Aerated lagoons, Uncovered lagoons | 0 |
| Siletz STP | Siletz | 0.08 | OR0020419 | Aug 2028 | Uncovered lagoons | 10 |
| North Powder STP | North Powder | 0.04 | OR0022403 | Sep 2028 | Aerated lagoons | 23 |
| Sheridan WWTP | Sheridan | — | OR0020648 | Sep 2028 | Uncovered lagoons | 19 |
| Junction City STP | Junction City | 0.55 | OR0026565 | Oct 2028 | Aerated lagoons | 167 |
| Yachats STP | Yachats | 0.14 | OR0020290 | Nov 2028 | Clarifiers | 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 September 11, 2026.