Montana NPDES permit search
Status, expiry and violations for 109 municipal wastewater permits · issued by MDEQ as MPDES permits
In short
How do I look up an NPDES permit in Montana?
Search this page by permit number or plant name for a municipal plant’s permit status, expiry date and violations. For the official file, search DEQ’s MPDES permit list or EPA’s list for tribal lands. EPA’s ECHO database shows the monitoring results and violations of every permit. The 180 industrial permits in Montana are listed in Klarifi with a free account.
Links to official sources checked September 2026.
Effective
47
Administratively continued
57
Expired
3
Plants with effluent violations, 3 years
67
Where to find official Montana NPDES records
Montana Department of Environmental Quality (MDEQ) runs the NPDES program in Montana under authorization from EPA Region 8, as the Montana Pollutant Discharge Elimination System (MPDES). It issues and enforces the permits and keeps the official file: applications, permits, fact sheets and monitoring reports. EPA Region 8 issues the permits on tribal lands. MDEQ website ↗
permit documents
The table on DEQ’s MPDES page: type the facility, permittee, town or permit number in its search box and click the permit number for the PDF. General permits are listed further down.
permit documents
Only facilities on tribal lands: search by facility name or permit number and click through to the permit and its documents.
permits · DMRs · inspections · violations · enforcement
EPA’s Enforcement and Compliance History Online. Search water facilities by permit number, name or city; the Detailed Facility Report lists inspections, violations and enforcement actions, and Effluent Charts plot monitoring results against the permit limits.
- Permit numbers
- Individual permits follow EPA’s format (MT0000019); DEQ numbers general permits MTG plus six digits and stormwater general permits MTR plus six digits.
- Discharge monitoring reports
- Through EPA’s NetDMR.
Industrial and commercial NPDES permits in Montana
Most NPDES permits are not held by municipal plants. EPA’s permit database lists 180 individual permits in force for industrial and commercial facilities in Montana (manufacturers, food processors, mines, power plants, landfills), 23 of them major dischargers, plus 1,685 facilities covered by a general permit, mostly for stormwater. 27 of the individual permits recorded at least one effluent violation in the last three years.
| Facility | Permit | Status | Expires | Effluent violations |
|---|
Unlock 180 industrial permits in Montana
Search every industrial and commercial discharger in Montana by name or permit number, with permit status, expiry and violation history. Free with a Klarifi account.
Industrial and commercial NPDES permits in Montana: permits in force (effective or administratively continued) held by facilities EPA does not class as publicly owned treatment works or federal facilities. Source: EPA ICIS-NPDES via Klarifi, October 2026.
Violations at Montana wastewater plants
67 of the 109 municipal plants on this page recorded at least one effluent violation, a monitored value above a permit limit, in the last three years, and 80 had a violation of any kind, including late or missing monitoring reports. Each plant’s page shows its own count. EPA’s enforcement records list 28 formal cases naming Montana wastewater plants, 3 of them since fiscal year 2020, with $712,825 in penalties assessed. Enforcement cases in Montana →
Permit renewals by year
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.
Largest permit holders in Montana
| Facility | City | Avg flow (MGD) | Design (MGD) | NPDES permit | Status | Expires | Violations (3y) |
|---|---|---|---|---|---|---|---|
| City Of Billings Wastewater Treatment Plant | Billings | 20.32 | — | MTR000459 | Effective | Jan 2028 | 7 |
| Town Of Lavina WWTF | Lavina | 18.51 | — | MTG580013 | Effective | Dec 2027 | 1 |
| Two Medicine Water Co. | Browning | 17.08 | — | MTDW0003I | Administratively continued | Jun 2024 | 0 |
| City Of Missoula WWTF No Exposure | Missoula | 9.3 | 12 | MT0022594 | Administratively continued | Apr 2020 | 7 |
| City Of Bozeman WWTP | Bozeman | 6.55 | — | MT0022608 | Administratively continued | May 2017 | 0 |
| City Of Kalispell WWTP | Kalispell | 3.96 | — | MT0021938 | Administratively continued | Jul 2020 | 11 |
| City Of Helena WWTP | Helena | 3.01 | — | MT0022641 | Administratively continued | Sep 2017 | 33 |
| Lewistown WWTP | Lewistown | 1.82 | 2.5 | MT0020044 | Administratively continued | Aug 2017 | 32 |
| Water Reclamation Facility | Livingston | 0.69 | 2.18 | MT0020435 | Administratively continued | Oct 2021 | 0 |
| Miles City WWTP | Miles City | 1.11 | 1.98 | MT0020001 | Administratively continued | Sep 2023 | 3 |
Montana NPDES permits: questions
NPDES permit search in other states
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 12, 2026.
Wastewater terms: NPDES permit · POTW · Significant industrial user · MGD · Biological nutrient removal · Tertiary treatment · all terms