Clean Water Act discharge permit · NPDES MTG310024
CAT CREEK MOSBY ELLIS SAND UNIT, Winnett, MT: NPDES MTG310024 discharge permit, effluent exceedances, inspections, penalties
- Administratively continuedPermit status
- MinorDischarger class
- 5Pollutants under a numeric limit
- 2Pollutants with an effluent exceedance
CAT CREEK MOSBY ELLIS SAND UNIT, held by CAT CREEK HOLDINGS LLC, holds NPDES permit MTG310024, which discharges to Unnamed Dry Coulee Of Musselshell R. EPA’s file records it issued July 27, 2015 and expiring April 30, 2020. 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 | CAT CREEK MOSBY ELLIS SAND UNIT |
|---|---|
| Permittee as filed | CAT CREEK HOLDINGS LLC |
| NPDES ID | MTG310024 |
| 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 |
| Issued | July 27, 2015 |
| Expiration date | April 30, 2020 |
| Address | Winnett, MT 59087 |
| Receiving water | UNNAMED DRY COULEE OF MUSSELSHELL R |
| Subwatershed | Musselshell River-Long Coulee (HUC 100402050104) |
Cited to the EPA ICIS-NPDES permit file (ECHO download).
Effluent limits and exceedances
- 22Pollutants on file
- 5Under a numeric limit
- 22With a violation of any kind
- 2With 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 |
|---|---|---|---|---|---|
| Oil & Grease | 0 | 25 | 2 | December 31, 2025 | 260% over the limit |
| Oil and grease, hexane extr method | 1 | 18 | 2 | December 31, 2021 | 160% over the limit |
| Sulfate, total [as SO4] | 2 | 22 | 0 | ||
| Flow rate | 0 | 21 | 0 | ||
| Solids, total dissolved | 0 | 21 | 0 | ||
| Flow rate | 1 | 19 | 0 | ||
| Solids, total dissolved [TDS] | 1 | 18 | 0 | ||
| Conductivity | 2 | 16 | 0 | ||
| Sulfate | 0 | 15 | 0 | ||
| Specific conductance | 0 | 9 | 0 | ||
| pH | 0 | 8 | 0 | ||
| Fluoride | 0 | 3 | 0 | ||
| Arsenic, total recoverable | 0 | 3 | 0 | ||
| Cobalt, total recoverable | 0 | 3 | 0 | ||
| Selenium, total recoverable | 0 | 3 | 0 | ||
| Zinc, total recoverable | 0 | 3 | 0 | ||
| Cadmium, total recoverable | 0 | 3 | 0 | ||
| Lead, total recoverable | 0 | 3 | 0 | ||
| Chromium, total recoverable | 0 | 3 | 0 | ||
| Copper, total recoverable | 0 | 3 | 0 | ||
| Nitrogen, nitrite total [as N] | 0 | 2 | 0 | ||
| Nitrogen, nitrate total [as N] | 0 | 2 | 0 |
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
- 2Single-event violations
| Date | What EPA recorded | Agency |
|---|---|---|
| August 1, 2017 | Reporting Violations - Failure to Submit DMRs | ST6 |
| August 1, 2017 | Monitoring Violations - Frequency of Sampling Violation | 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.
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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 MTG310024 there.
Nearby on the register
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Figures from EPA’s ICIS-NPDES download, loaded September 14, 2026.