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Clean Water Act discharge permit · NPDES MT0022594

CITY OF MISSOULA WWTP, Missoula, MT: NPDES MT0022594 discharge permit, effluent exceedances, inspections, penalties

CITY OF MISSOULA WWTP, held by CITY OF MISSOULA, holds NPDES permit MT0022594, which discharges to Clark Fork River. EPA’s file records it issued September 26, 2006 and expiring October 31, 2011. 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 filedCITY OF MISSOULA WWTP
Permittee as filedCITY OF MISSOULA
NPDES IDMT0022594
Permit statusAdministratively continued (past its expiration date and still in force until reissued)
Permit typeIndividual permit
Discharger classMajor discharger
Facility typePublicly owned treatment works
ProgramPublicly owned treatment works
IssuedSeptember 26, 2006
Expiration dateOctober 31, 2011
Issuing agencyMONTANA DEQ
AddressMissoula, MT 59802
Receiving waterCLARK FORK RIVER
SubwatershedClark Fork River-Marshall Creek (HUC 170102040104)

Cited to the EPA ICIS-NPDES permit file (ECHO download).

Effluent limits and exceedances

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 measureLimitsViolations, any kindEffluent exceedancesLatest exceedanceLargest exceedance, as filed
E. coli, MTEC-MF8207August 31, 201514,167% over the limit
Nitrogen, ammonia total [as N]2265March 31, 202331% over the limit
BOD, carbonaceous [5 day, 20 C]6184April 30, 202699,999% over the limit
Copper, total recoverable264November 30, 202132% over the limit
Pass/Fail Static Renewal 96Hr Acute Pimephales Promelas164June 30, 2003
Phosphorus, total [as P]13473June 30, 202611% over the limit
Oil and grease173November 30, 2007144% over the limit
Nitrogen, total [as N]11321June 30, 20081% over the limit
Solids, total suspended8261November 30, 2006748% over the limit
pH8131January 31, 2015
BOD, carbonaceous, percent removal231April 30, 202699,999% over the limit
Chlorine, total residual131July 31, 200019% over the limit
Pass/Fail Static Renewal 48Hr Acute Ceriodaphnia dubia131December 31, 2013
Nitrite + Nitrate total [as N]4230
Phosphate, ortho, dissolved [as P]0210
Nitrogen, Kjeldahl, total [as N]3180
Chemical Oxygen Demand [COD]2120
Flow rate2100
Carbonaceous BOD, 5 day, 20 deg C filtrd2100
Specific conductance360
Solids, total dissolved [TDS]450
Flow, in conduit or thru treatment plant640
Temperature, water deg. centigrade340
Solids, suspended percent removal230
Cyanide, total [as CN]130
Coliform, fecal general030
Cadmium, total recoverable220
Lead, total recoverable220
Antimony, total recoverable220
Mercury, total recoverable220
Total phenols120
Oxygen, dissolved [DO]310
Arsenic, total recoverable210
Water level at sample collection time210
Hardness, total [as CaCO3]110
Selenium, total recoverable110
Thallium, total recoverable110
Beryllium, total recoverable [as Be]110
Nickel, total recoverable110
Silver total recoverable110
Zinc, total recoverable110
Chromium, total recoverable110
Oil and grease visual110
Flow rate010
Moisture content200
Conductivity100
Sodium adsorption ratio100

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

DateWhat EPA recordedAgency
February 27, 2018Management Practice Violations - Failure to Maintain RecordsST6
February 27, 2018Monitoring Violations - Improper Analysis or Lab ErrorST6
February 27, 2018Reporting Violations - Failure to submit required report (non-DMR non-pretreatment)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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Nearby on the register

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

What this page shows

This public-records page covers the Clean Water Act discharge permit NPDES MT0022594 for the CITY OF MISSOULA WWTP in Missoula, MT, held by CITY OF MISSOULA and discharging to the Clark Fork River in the Clark Fork River-Marshall Creek watershed (HUC 170102040104). The permit is listed as administratively continued, a Major discharger class, with 44 pollutants under a numeric limit and 13 pollutants with an effluent exceedance.