Montana wastewater permits expiring in 2026
11 NPDES permits · 4 MGD combined average flow
11 publicly owned wastewater treatment plants in Montana hold NPDES permits that expire during 2026, issued by Montana 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) |
|---|---|---|---|---|---|---|
| Forsyth WWTP | Forsyth | 0.19 | MT0021288 | Jan 2026 | — | 0 |
| White Sulphur Springs WWTF | White Sulphur Springs | 0.05 | MT0020699 | May 2026 | Uncovered lagoons | 41 |
| Town Of Jordan Wastewater Treatmetn Facility | Jordan | — | MT0021385 | Jul 2026 | Uncovered lagoons | 371 |
| Havre WWTF | Havre | 1.64 | MT0022535 | Aug 2026 | Clarifiers | 0 |
| Choteau Sewage Treatment Ponds | Choteau | 0.25 | MT0020052 | Aug 2026 | Aerated lagoons, Carrousels / oxidation ditches, Biogas silos | 3 |
| Alberton WWTP | Alberton | 0.02 | MT0021555 | Oct 2026 | Aerated lagoons | 23 |
| Fort Benton WWTP | Fort Benton | — | MT0021601 | Oct 2026 | Aerated lagoons, Uncovered lagoons | 4 |
| City Of Glasgow Parks Maintenance Bldg | Glasgow | 0.66 | MT0021211 | Nov 2026 | — | 21 |
| Town Of Culbertson Domestic WWTF | Culbertson | 0.06 | MT0031798 | Nov 2026 | Uncovered lagoons | 42 |
| Ekalaka WWTF | Ekalaka | 0.0019 | MT0020371 | Nov 2026 | Aerated lagoons | 105 |
| City Of Hamilton Wastewater Treatment Plant | Hamilton | 0.79 | MT0020028 | Dec 2026 | Carrousels / oxidation ditches | 0 |
Montana 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.