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Uscoe Libby Dam

Federal facility (Water, Sewer, And Utility Lines), Libby, Montana. NPDES permit MT0022390 expired Sep 30, 2026; its limits still apply. Last 12 months: no values over a limit, 9 of 83 reports late. Source: EPA ECHO, Oct 22, 2026.

Reports due
About 28 days after each period: outfall 001 form A monthly (17 values), outfall 001 form Q quarterly (2 values), outfall 001 form Q2 quarterly (11 values), outfall 002 form A monthly (6 values), outfall 003 form A monthly (6 values), outfall 003 form B monthly (6 values), and 3 more forms
Last report on file
August 2026
Oct 2024 – Sep 2025
0 values over a limit, 64 required values missing, 37 of 92 reports late

Limits in force (68)

ParameterStatisticLimitMonthsOutfall
Temperature, water deg. centigrademinimumreport only (deg C)all year001
Temperature, water deg. centigrademonthly averagereport only (deg C)all year001
Temperature, water deg. centigrademaximumreport only (deg C)all year001
Flow ratemonthly averagereport only (MGD)all year001
Flow ratedaily maximumreport only (MGD)all year001
BOD, 5-day, 20 deg. Cmonthly average≤ 30 mg/Lall year001
BOD, 5-day, 20 deg. Cdaily maximum≤ 45 mg/Lall year001
BOD, 5-day, 20 deg. Cmonthly average≤ 1.5 lb/dall year001
BOD, 5-day, 20 deg. Cmaximum weekly average≤ 2.25 lb/dall year001
BOD, 5-day, 20 deg. Csingle samplereport only (mg/L)all year001
pHminimum≥ 6 SUall year001
pHmaximum≤ 9 SUall year001
Solids, total suspendedmonthly average≤ 30 mg/Lall year001
Solids, total suspendedmaximum weekly average≤ 45 mg/Lall year001
Solids, total suspendedmonthly average≤ 1.5 lb/dall year001
Solids, total suspendedmaximum weekly average≤ 2.25 lb/dall year001
Solids, total suspendedsingle samplereport only (mg/L)all year001
Oil and grease, hexane extr methodsingle samplereport only (mg/L)all year001
Oil and grease, hexane extr methoddaily maximumreport only (mg/L)all year001
Nitrogen, total [as N]single samplereport only (mg/L)all year001
Nitrogen, total [as N]single samplereport only (lb/d)all year001
Nitrogen, ammonia total [as N]single samplereport only (mg/L)all year001
Nitrogen, Kjeldahl, total [as N]single samplereport only (mg/L)all year001
Nitrite + Nitrate total [as N]single samplereport only (mg/L)all year001
Phosphorus, total [as P]single samplereport only (mg/L)all year001
Phosphorus, total [as P]single samplereport only (lb/d)all year001
E. coli, MTEC-MFmonthly geometric mean≤ 630 #/100mLJan, Feb, Mar, Nov, Dec001
E. coli, MTEC-MFmonthly geometric mean≤ 126 #/100mLApr–Oct001
E. coli, MTEC-MFdaily maximum≤ 1260 #/100mLJan, Feb, Mar, Nov, Dec001
E. coli, MTEC-MFdaily maximum≤ 252 #/100mLApr–Oct001
BOD, 5-day, percent removalminimum≥ 85 %all year001
Solids, suspended percent removalminimum≥ 85 %all year001
Flow ratemonthly averagereport only (MGD)all year002
Flow ratedaily maximumreport only (MGD)all year002
pHminimumreport only (SU)all year002
pHmonthly averagereport only (SU)all year002
pHmaximumreport only (SU)all year002
Oil and grease, hexane extr methoddaily maximumreport only (mg/L)Mar, Jun, Sep, Dec002
Temperature, water deg. fahrenheitdaily minimumreport only (deg F)all year003
Temperature, water deg. fahrenheitdaily minimumreport only (deg F)all year003
Temperature, water deg. fahrenheitdaily minimumreport only (deg F)all year003
Temperature, water deg. fahrenheitdaily minimumreport only (deg F)all year003
Temperature, water deg. fahrenheitdaily minimumreport only (deg F)all year003
Temperature, water deg. fahrenheitmonthly averagereport only (deg F)all year003
Temperature, water deg. fahrenheitmonthly averagereport only (deg F)all year003
Temperature, water deg. fahrenheitmonthly averagereport only (deg F)all year003
Temperature, water deg. fahrenheitmonthly averagereport only (deg F)all year003
Temperature, water deg. fahrenheitmonthly averagereport only (deg F)all year003
Temperature, water deg. fahrenheitdaily maximumreport only (deg F)all year003
Temperature, water deg. fahrenheitdaily maximumreport only (deg F)all year003
Temperature, water deg. fahrenheitdaily maximumreport only (deg F)all year003
Temperature, water deg. fahrenheitdaily maximumreport only (deg F)all year003
Temperature, water deg. fahrenheitdaily maximumreport only (deg F)all year003
Flow ratemonthly averagereport only (MGD)all year003
Flow ratemonthly averagereport only (MGD)all year003
Flow ratemonthly averagereport only (MGD)all year003
Flow ratemonthly averagereport only (MGD)all year003
Flow ratemonthly averagereport only (MGD)all year003
Flow ratedaily maximumreport only (MGD)all year003
Flow ratedaily maximumreport only (MGD)all year003
Flow ratedaily maximumreport only (MGD)all year003
Flow ratedaily maximumreport only (MGD)all year003
Flow ratedaily maximumreport only (MGD)all year003
Oil and grease, hexane extr methodsingle grab samplereport only (mg/L)Mar, Jun, Sep, Dec003
Oil and grease, hexane extr methodsingle grab samplereport only (mg/L)Mar, Jun, Sep, Dec003
Oil and grease, hexane extr methodsingle grab samplereport only (mg/L)Mar, Jun, Sep, Dec003
Oil and grease, hexane extr methodsingle grab samplereport only (mg/L)Mar, Jun, Sep, Dec003
Oil and grease, hexane extr methodsingle grab samplereport only (mg/L)Mar, Jun, Sep, Dec003

How strict are these limits?

Cited limits by parameter: Montana's rules and the federal ones.

Same industry: the 4 Heavy Construction permits in Montana.

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On EPA ECHO: Facility report · DMR history

Your permit document is the final word. As JSON: /api/v1/permits/MT0022390 · MCP: https://passage-data.com/mcp