Clean Water Act discharge permit · NPDES MTX000331
GRASS VALLEY GARDENS RESIDENTIAL SUBDIVISION, Missoula, MT: NPDES MTX000331 discharge permit, effluent exceedances, inspections, penalties
- EffectivePermit status
- MinorDischarger class
- 13Pollutants under a numeric limit
- 0Pollutants with an effluent exceedance
GRASS VALLEY GARDENS RESIDENTIAL SUBDIVISION, held by Grass Valley Gardens LLC, holds NPDES permit MTX000331, which discharges to Ground Water. EPA’s file records it issued July 21, 2025 and expiring August 31, 2030. 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 | GRASS VALLEY GARDENS RESIDENTIAL SUBDIVISION |
|---|---|
| Permittee as filed | Grass Valley Gardens LLC |
| NPDES ID | MTX000331 |
| Permit status | Effective |
| Permit type | State-issued individual permit |
| Discharger class | Minor discharger |
| Facility type | Not a publicly owned treatment works |
| Issued | July 21, 2025 |
| Expiration date | August 31, 2030 |
| Address | Missoula, MT 59808 |
| Receiving water | GROUND WATER |
| Subwatershed | O'Keefe Creek (HUC 170102040204) |
Cited to the EPA ICIS-NPDES permit file (ECHO download).
Effluent limits and exceedances
- 13Pollutants on file
- 13Under a numeric limit
- 8With 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 |
|---|---|---|---|---|---|
| Nitrogen, total [as N] | 5 | 12 | 0 | ||
| Nitrogen, ammonia total [as N] | 3 | 6 | 0 | ||
| Nitrogen, Kjeldahl, total [as N] | 3 | 6 | 0 | ||
| Nitrite + Nitrate total [as N] | 3 | 6 | 0 | ||
| Phosphorus, total [as P] | 2 | 6 | 0 | ||
| Flow rate | 1 | 3 | 0 | ||
| BOD, 5-day, 20 deg. C | 1 | 3 | 0 | ||
| Solids, total suspended | 1 | 3 | 0 | ||
| Temperature, water deg. centigrade | 1 | 0 | 0 | ||
| Conductivity | 1 | 0 | 0 | ||
| Chloride [as Cl] | 1 | 0 | 0 | ||
| Water level at sample collection time | 1 | 0 | 0 | ||
| Monitoring well level from the surface | 1 | 0 | 0 |
EPA’s effluent violation file records no exceedance of a numeric limit for NPDES MTX000331.
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
- 0Single-event violations
EPA’s single-event violation file, as loaded, holds no violation for NPDES MTX000331.
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, MTX000331.
Start the watch
- One permit holder — $99/month
- One watershed — $2,990/year
- One state — $4,990/year
- The whole register — $18,000/year
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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 MTX000331 there.
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Figures from EPA’s ICIS-NPDES download, loaded September 15, 2026.