Clean Water Act discharge permit · NPDES MTG010155
ROCK PORT COLONY, Pendroy, MT: NPDES MTG010155 discharge permit, effluent exceedances, inspections, penalties
- Administratively continuedPermit status
- MinorDischarger class
- 0Pollutants under a numeric limit
- 0Pollutants with an effluent exceedance
ROCK PORT COLONY holds NPDES permit MTG010155, which discharges to South Fork Dry Fork Marias River. EPA’s file records it issued August 18, 2020 and expiring October 31, 2023. The status and dates are as EPA’s permit file stood when Velarion loaded it (September 14, 2026); EPA’s free Detailed Facility Report on ECHO carries the permit’s current standing.
Identity
| Facility as filed | ROCK PORT COLONY |
|---|---|
| Permittee as filed | ROCK PORT COLONY |
| NPDES ID | MTG010155 |
| Permit status | Administratively continued (past its expiration date and still in force until reissued) |
| Permit type | Coverage under a general permit |
| Discharger class | Minor discharger |
| Facility type | Not a publicly owned treatment works |
| Program | Concentrated animal feeding operations |
| Issued | August 18, 2020 |
| Expiration date | October 31, 2023 |
| Address | Pendroy, MT 59467 |
| Receiving water | SOUTH FORK DRY FORK MARIAS RIVER |
| Subwatershed | South Fork Dry Fork Marias River (HUC 100302030601) |
Cited to the EPA ICIS-NPDES permit file (ECHO download).
Effluent limits and exceedances
- 9Pollutants on file
- 0Under a numeric limit
- 9With a violation of any kind
- 0With an effluent exceedance
An effluent exceedance is a discharge monitoring report value over the permit’s numeric limit (EPA’s violation code E90). A violation of any kind also counts a report not filed. Each row is EPA’s own count for that pollutant.
| Pollutant or measure | Limits | Violations, any kind | Effluent exceedances | Latest exceedance | Largest exceedance, as filed |
|---|---|---|---|---|---|
| Nitrite + Nitrate total [as N] | 0 | 2 | 0 | ||
| BOD, 5-day, 20 deg. C | 0 | 1 | 0 | ||
| pH | 0 | 1 | 0 | ||
| Solids, total suspended | 0 | 1 | 0 | ||
| Nitrogen, total [as N] | 0 | 1 | 0 | ||
| Nitrogen, ammonia total [as N] | 0 | 1 | 0 | ||
| Phosphorus, total [as P] | 0 | 1 | 0 | ||
| E. coli, MTEC-MF | 0 | 1 | 0 | ||
| Water level at sample collection time | 0 | 1 | 0 |
EPA’s effluent violation file records no exceedance of a numeric limit for NPDES MTG010155.
Cited to the EPA ICIS-NPDES limits and effluent violations files (ECHO download); up to 60 rows shown, most exceedances first.
Inspections, violations and enforcement
- 3Single-event violations
| Date | What EPA recorded | Agency |
|---|---|---|
| August 7, 2025 | WW CAFO - Failure to Maintain Records or Meet Record Keeping Requirements | ST6 |
| August 7, 2025 | WW CAFO - Monitoring Violations - No Depth Marker in Storage Pond | ST6 |
| August 7, 2025 | WW CAFO - Best Management Practice Deficiencies | ST6 |
Velarion’s copy of EPA’s ICIS-NPDES files does not include the inspections, formal enforcement actions and informal enforcement actions files, so this page shows none of them. EPA’s free Detailed Facility Report on ECHO lists this permit’s inspections, enforcement actions and penalties.
Cited to the EPA ICIS-NPDES violation, inspection and enforcement files (ECHO download); up to 50 rows of each shown, newest first.
Watch this permit
One permit holder, $99/month. Watch the register for one permit holder and the places and receiving waters tied to its permits. Choose “One permit holder” and enter this permit’s NPDES ID, MTG010155.
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EPA publishes a free Detailed Facility Report for every permit on ECHO: its compliance status quarter by quarter, its inspections, and its enforcement actions and penalties. EPA also sends free notices of new inspections and enforcement actions through ECHO Notify; enter NPDES ID MTG010155 there.
Nearby on the register
Figures from EPA’s ICIS-NPDES download, loaded September 14, 2026.