Clean Water Act discharge permit · NPDES MTX000122
CORVALLIS WWTF, Corvallis, MT: NPDES MTX000122 discharge permit, effluent exceedances, inspections, penalties
- Administratively continuedPermit status
- MinorDischarger class
- 13Pollutants under a numeric limit
- 4Pollutants with an effluent exceedance
CORVALLIS WWTF, held by CORVALLIS COUNTY SEWER DISTRICT, holds NPDES permit MTX000122, which discharges to Ground Water. EPA’s file records it issued May 17, 2007 and expiring June 30, 2012. The status and dates are as EPA’s permit file stood when Velarion loaded it (September 15, 2026); EPA’s free Detailed Facility Report on ECHO carries the permit’s current standing.
Identity
| Facility as filed | CORVALLIS WWTF |
|---|---|
| Permittee as filed | CORVALLIS COUNTY SEWER DISTRICT |
| NPDES ID | MTX000122 |
| Permit status | Administratively continued (past its expiration date and still in force until reissued) |
| Permit type | State-issued individual permit |
| Discharger class | Minor discharger |
| Facility type | Not a publicly owned treatment works |
| Program | Publicly owned treatment works |
| Issued | May 17, 2007 |
| Expiration date | June 30, 2012 |
| Issuing agency | MONTANA DEQ |
| Address | Corvallis, MT 59828 |
| Receiving water | GROUND WATER |
| Subwatershed | Willow Creek (HUC 170102051006) |
Cited to the EPA ICIS-NPDES permit file (ECHO download).
Effluent limits and exceedances
- 17Pollutants on file
- 13Under a numeric limit
- 17With a violation of any kind
- 4With 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 |
|---|---|---|---|---|---|
| E. coli, MTEC-MF | 10 | 60 | 30 | August 31, 2025 | 99,999% over the limit |
| Nitrogen, total [as N] | 10 | 50 | 9 | April 30, 2025 | 206% over the limit |
| Coliform, fecal general | 0 | 45 | 6 | December 31, 2005 | 100% over the limit |
| Nitrogen, inorganic total | 0 | 32 | 1 | May 31, 2004 | 3% over the limit |
| Phosphorus, total [as P] | 10 | 76 | 0 | ||
| Oxygen, dissolved [DO] | 6 | 76 | 0 | ||
| Nitrite + Nitrate total [as N] | 7 | 70 | 0 | ||
| Chloride [as Cl] | 7 | 67 | 0 | ||
| Nitrogen, ammonia total [as N] | 7 | 60 | 0 | ||
| Nitrogen, Kjeldahl, total [as N] | 6 | 53 | 0 | ||
| BOD, 5-day, 20 deg. C | 6 | 49 | 0 | ||
| Solids, total suspended | 6 | 49 | 0 | ||
| Flow rate | 0 | 29 | 0 | ||
| Temperature, water deg. fahrenheit | 0 | 28 | 0 | ||
| Flow rate | 4 | 18 | 0 | ||
| Specific conductance | 1 | 14 | 0 | ||
| Water level at sample collection time | 1 | 14 | 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 |
|---|---|---|
| June 9, 2023 | Monitoring Violations - Invalid/Unrepresentative Sample | ST6 |
| June 9, 2023 | Reporting Violations - Improper/ Incorrect Reporting | 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, MTX000122.
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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 MTX000122 there.
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Figures from EPA’s ICIS-NPDES download, loaded September 15, 2026.