Montana wastewater permits expiring in 2027
27 NPDES permits · 3 MGD combined average flow
27 publicly owned wastewater treatment plants in Montana hold NPDES permits that expire during 2027, 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) |
|---|---|---|---|---|---|---|
| Superior Wastewater Treatment Facility | Superior | 0.03 | MT0020664 | Feb 2027 | Aerated lagoons | 24 |
| Town Of Valier WWTF | Valier | — | MT0021792 | Feb 2027 | Uncovered lagoons | 5 |
| Bozeman Water Treatment Plant | Bozeman | 0.13 | MTX000224 | Mar 2027 | — | 4 |
| Agency Lagoon | Box Elder | — | MTG589701 | Mar 2027 | Aerated lagoons, Uncovered lagoons | 4 |
| Azure Lagoon | Box Elder | — | MTG589703 | Mar 2027 | Uncovered lagoons | 78 |
| Crow Agency Lagoon | Crow Agency | — | MTG589009 | Mar 2027 | Aerated lagoons | 850 |
| Lower Dry Fork Lagoon | Box Elder | — | MTG589702 | Mar 2027 | Uncovered lagoons | 114 |
| Multi-Community Lagoon | Box Elder | — | MTG589705 | Mar 2027 | Uncovered lagoons | 0 |
| Red Lodge WWTF | Red Lodge | 0.57 | MT0020478 | Apr 2027 | Aerated lagoons | 3 |
| Three Forks WWTF | Three Forks | 0.31 | MT0020401 | Apr 2027 | Covered lagoons, Uncovered lagoons | 5 |
| Town Of Plains WWTP | Plains | 0.1 | MT0030465 | Apr 2027 | Aerated lagoons, Uncovered lagoons | 10 |
| City Of Glendive Water Resource & Recovery Facility | Glendive | 0.84 | MT0021628 | May 2027 | — | 3 |
| Ronan City WWTF | Ronan | 0.2 | MT0021474 | Jun 2027 | Aerated lagoons, Uncovered lagoons | 523 |
| Gardiner Wastewater Treatment Facility | Gardiner | 0.13 | MT0022705 | Sep 2027 | Aerated lagoons, Uncovered lagoons | 119 |
| City Of Laurel, Water Treatment Plant | Laurel | 0.29 | MT0030261 | Oct 2027 | — | 0 |
| Joliet WWTP | Joliet | 0.06 | MT0020249 | Dec 2027 | Aerated lagoons | 28 |
| Brady County Water Sewer District | Brady | — | MTG580022 | Dec 2027 | Uncovered lagoons | — |
| City Of Baker WWTF | Baker | — | MTG580029 | Dec 2027 | Uncovered lagoons | 32 |
| Town Of Broadus WWTF | Broadus | — | MTG580015 | Dec 2027 | Uncovered lagoons | 24 |
| Town Of Darby WWTF | Darby | — | MTG580011 | Dec 2027 | Aerated lagoons | 13 |
| Town Of Fairfield WWTP | Fairfield | — | MTG580003 | Dec 2027 | Uncovered lagoons | 13 |
| Town Of Fort Peck WWTF | Fort Peck | — | MTG580019 | Dec 2027 | Uncovered lagoons | 0 |
| Town Of Geraldine WWTF | Geraldine | — | MTG580016 | Dec 2027 | Aerated lagoons, Uncovered lagoons | 54 |
| Town Of Lavina WWTF | Lavina | — | MTG580013 | Dec 2027 | Uncovered lagoons | 1 |
| Town Of Nashua WWTF | Nashua | — | MTG580034 | Dec 2027 | Uncovered lagoons | 60 |
| Town Of Saco | Saco | — | MTG580012 | Dec 2027 | Uncovered lagoons | 12 |
| Town Of Terry WWTF | Terry | — | MTG580017 | Dec 2027 | Uncovered lagoons | 390 |
Montana permit renewals in 2027: 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.