Clean Water Act discharge permit · NPDES MTR102519

NORTHWESTERN ENERGY - MILL CREEK SUBSTATION, Opportunity, MT: NPDES MTR102519 discharge permit, effluent exceedances, inspections, penalties

EffectivePermit status
MinorDischarger class
0Pollutants under a numeric limit
0Pollutants with an effluent exceedance

NORTHWESTERN ENERGY - MILL CREEK SUBSTATION, held by NORTHWESTERN ENERGY, holds NPDES permit MTR102519, which discharges to Mill Creek. EPA’s file records it issued March 19, 2007 and expiring December 31, 2007. 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.

What the register holds for NORTHWESTERN ENERGY - MILL CREEK SUBSTATION: its NPDES ID, its permit type and status, its dates, its address in Opportunity, Montana, its receiving water. EPA’s effluent violation file and its single-event violation file hold no violation for NPDES MTR102519.

Identity

Facility as filed	NORTHWESTERN ENERGY - MILL CREEK SUBSTATION
Permittee as filed	NORTHWESTERN ENERGY
NPDES ID	MTR102519
Permit status	Effective
Permit type	Coverage under a general permit
Discharger class	Minor discharger
Facility type	Not a publicly owned treatment works
Program	Construction stormwater
Issued	March 19, 2007
Expiration date	December 31, 2007
Issuing agency	MONTANA DEQ
Address	Opportunity, MT 59711
Receiving water	MILL CREEK
Subwatershed	Silver Bow Creek-White Pine Creek (HUC 170102010209)
Other EPA IDs (FRS)	RCRA handler MTD981545049

Cited to the EPA ICIS-NPDES permit file (ECHO download); cross-program IDs from EPA’s FRS facility-registry crosswalk.

Effluent limits and exceedances

0Pollutants on file
0Under a numeric limit
0With a violation of any kind
0With an effluent exceedance

EPA’s limits and effluent violation files hold no pollutant row for NPDES MTR102519.

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 MTR102519.

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, MTR102519.

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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 MTR102519 there.

Nearby on the register

Figures from EPA’s ICIS-NPDES download, loaded September 15, 2026.

This public-records page covers NPDES permit MTR102519, held by NORTHWESTERN ENERGY for the Mill Creek Substation in Opportunity, Montana, which discharges to Mill Creek. The register lists the permit as Effective, a minor discharger class with 0 pollutants under a numeric limit and 0 pollutants with an effluent exceedance. The permit was issued March 19, 2007 and expires December 31, 2007, and EPA's file records no violation for it.