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City of Big Timber

Sewage treatment plant, Big Timber, Montana. NPDES permit MT0020753 expired Apr 30, 2017; its limits still apply. Last 12 months: over a limit 11 times (last September 2026), 1 of 14 reports late. Source: EPA ECHO, Oct 22, 2026.

Reports due
About 28 days after each period: form A monthly (50 values), form S twice a year
Last report on file
September 2026
Oct 2024 – Sep 2025
20 values over a limit, 0 required values missing, 2 of 14 reports late

Last 12 months (Oct 1, 2025 – Sep 30, 2026)

Period endingParameterReportedLimitOver by
May 2026Solids, suspended percent removal, monthly average minimum83.1 %≥ 85 %13%
May 2026Solids, total suspended, monthly average50.5 mg/L≤ 30 mg/L68%
May 2026Solids, total suspended, monthly average82.47 lb/d≤ 77 lb/d7%
May 2026Solids, total suspended, maximum weekly average125.4 lb/d≤ 116 lb/d8%
May 2026Solids, total suspended, maximum weekly average64 mg/L≤ 45 mg/L42%
June 2026Solids, total suspended, monthly average48.5 mg/L≤ 30 mg/L62%
June 2026Solids, total suspended, monthly average91.56 lb/d≤ 77 lb/d19%
June 2026Solids, total suspended, maximum weekly average51 mg/L≤ 45 mg/L13%
July 2026Solids, total suspended, monthly average40 mg/L≤ 30 mg/L33%
August 2026Solids, suspended percent removal, monthly average minimum76.1 %≥ 85 %59%
September 2026Solids, suspended percent removal, monthly average minimum81.4 %≥ 85 %24%

Limits in force (68)

ParameterStatisticLimitMonths
Temperature, water deg. fahrenheitmonthly averagereport only (deg F)all year
Temperature, water deg. fahrenheitdaily maximumreport only (deg F)all year
Flow ratemonthly averagereport only (MGD)all year
Flow ratedaily maximumreport only (MGD)all year
BOD, 5-day, 20 deg. Cmonthly average≤ 30 mg/Lall year
BOD, 5-day, 20 deg. Cmonthly average≤ 42 mg/Lall year
BOD, 5-day, 20 deg. Cmaximum weekly average≤ 45 mg/Lall year
BOD, 5-day, 20 deg. Cmaximum weekly average≤ 63 mg/Lall year
BOD, 5-day, 20 deg. Cmonthly average≤ 68 lb/dall year
BOD, 5-day, 20 deg. Cmonthly average≤ 95.2 lb/dall year
BOD, 5-day, 20 deg. Cmaximum 7-day average≤ 102 lb/dall year
BOD, 5-day, 20 deg. Cmaximum 7-day average≤ 143 lb/dall year
BOD, 5-day, 20 deg. Cmonthly averagereport only (mg/L)all year
BOD, 5-day, 20 deg. Cmaximum weekly averagereport only (mg/L)all year
pHinstantaneous minimum≥ 6 SUall year
pHinstantaneous minimum≥ 5.5 SUall year
pHinstantaneous maximum≤ 9 SUall year
pHinstantaneous maximum≤ 9.5 SUall year
Solids, total suspendedmonthly average≤ 30 mg/Lall year
Solids, total suspendedmonthly average≤ 42 mg/Lall year
Solids, total suspendedmaximum weekly average≤ 45 mg/Lall year
Solids, total suspendedmaximum weekly average≤ 63 mg/Lall year
Solids, total suspendedmonthly average≤ 77 lb/dall year
Solids, total suspendedmonthly average≤ 108 lb/dall year
Solids, total suspendedmaximum weekly average≤ 116 lb/dall year
Solids, total suspendedmaximum weekly average≤ 162.4 lb/dall year
Solids, total suspendedmonthly averagereport only (mg/L)all year
Solids, total suspendedmaximum weekly averagereport only (mg/L)all year
Oil and grease, hexane extr methodvaluereport only (mg/L)all year
Nitrogen, total [as N]monthly averagereport only (mg/L)all year
Nitrogen, total [as N]maximum weekly averagereport only (mg/L)all year
Nitrogen, total [as N]monthly averagereport only (lb/d)all year
Nitrogen, total [as N]maximum weekly averagereport only (lb/d)all year
Nitrogen, ammonia total [as N]monthly averagereport only (mg/L)all year
Nitrogen, ammonia total [as N]maximum weekly averagereport only (mg/L)all year
Nitrogen, Kjeldahl, total [as N]monthly averagereport only (mg/L)all year
Nitrogen, Kjeldahl, total [as N]maximum weekly averagereport only (mg/L)all year
Nitrite + Nitrate total [as N]monthly averagereport only (mg/L)all year
Nitrite + Nitrate total [as N]maximum weekly averagereport only (mg/L)all year
Phosphorus, total [as P]monthly averagereport only (mg/L)all year
Phosphorus, total [as P]maximum weekly averagereport only (mg/L)all year
Phosphorus, total [as P]monthly averagereport only (lb/d)all year
Phosphorus, total [as P]maximum weekly averagereport only (lb/d)all year
Iron, total recoverablemonthly averagereport only (ug/L)all year
Iron, total recoverabledaily maximumreport only (ug/L)all year
Iron, total recoverablemonthly averagereport only (lb/d)all year
Iron, total recoverabledaily maximumreport only (lb/d)all year
Lead, total recoverablemonthly averagereport only (ug/L)all year
Lead, total recoverabledaily maximumreport only (ug/L)all year
Lead, total recoverablemonthly averagereport only (lb/d)all year
Lead, total recoverabledaily maximumreport only (lb/d)all year
Copper, total recoverablemonthly averagereport only (ug/L)all year
Copper, total recoverabledaily maximumreport only (ug/L)all year
Copper, total recoverablemonthly averagereport only (lb/d)all year
Copper, total recoverabledaily maximumreport only (lb/d)all year
E. coli, MTEC-MFmonthly averagereport only (CFU/100mL)Apr–Oct
E. coli, MTEC-MFmonthly averagereport only (CFU/100mL)Jan, Feb, Mar, Nov, Dec
E. coli, MTEC-MFmaximum weekly averagereport only (CFU/100mL)Apr–Oct
E. coli, MTEC-MFmaximum weekly averagereport only (CFU/100mL)Jan, Feb, Mar, Nov, Dec
Chlorine, total residualmonthly average≤ .1 mg/Lall year
Chlorine, total residualdaily maximum≤ .1 mg/Lall year
Coliform, fecal generalmonthly average≤ 480 CFU/100mLApr–Oct
Coliform, fecal generalmonthly average≤ 2400 CFU/100mLJan, Feb, Mar, Nov, Dec
Coliform, fecal generalmaximum weekly average≤ 240 CFU/100mLApr–Oct
Coliform, fecal generalmaximum weekly average≤ 1200 CFU/100mLJan, Feb, Mar, Nov, Dec
BOD, 5-day, percent removalmonthly average minimum≥ 85 %all year
BOD, 5-day, percent removalmonthly average minimum≥ 65 %all year
Solids, suspended percent removalmonthly average minimum≥ 85 %all year

How strict are these limits?

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

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On EPA ECHO: Facility report · DMR history

Your permit document is the final word. As JSON: /api/v1/permits/MT0020753 · MCP: https://passage-data.com/mcp