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Town of Grass Range

Sewage treatment plant, Grass Range, Montana. NPDES permit MT0030309 expired Sep 30, 2026; its limits still apply. Last 12 months: no values over a limit. Source: EPA ECHO, Oct 22, 2026.

Reports due
About 28 days after each period: form A monthly (27 values), form Q quarterly (3 values)
Last report on file
September 2026
Oct 2024 – Sep 2025
0 values over a limit, 0 required values missing, 0 of 16 reports late

Limits in force (32)

ParameterStatisticLimitMonths
Temperature, water deg. centigradesingle samplereport only (deg C)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. Cmaximum weekly average≤ 45 mg/Lall year
BOD, 5-day, 20 deg. Cmonthly average≤ 9.5 lb/dall year
BOD, 5-day, 20 deg. Cmaximum weekly average≤ 14.3 lb/dall year
BOD, 5-day, 20 deg. Cmonthly averagereport only (mg/L)all year
pHdaily minimum≥ 6 SUall year
pHdaily maximum≤ 9 SUall year
pHsingle samplereport only (SU)all year
Solids, total suspendedmonthly average≤ 30 mg/Lall year
Solids, total suspendedmaximum weekly average≤ 45 mg/Lall year
Solids, total suspendedmonthly average≤ 9.5 lb/dall year
Solids, total suspendedmaximum weekly average≤ 14.3 lb/dall year
Solids, total suspendedmonthly averagereport only (mg/L)all year
Oil and grease, hexane extr methoddaily maximum≤ 10 mg/Lall year
Nitrogen, total [as N]monthly averagereport only (mg/L)all year
Nitrogen, ammonia total [as N]monthly averagereport only (mg/L)all year
Nitrogen, ammonia total [as N]daily maximumreport only (mg/L)all year
Nitrogen, ammonia total [as N]single samplereport only (mg/L)all year
Nitrogen, Kjeldahl, total [as N]monthly averagereport only (mg/L)all year
Nitrite + Nitrate total [as N]monthly averagereport only (mg/L)all year
Phosphorus, total [as P]monthly averagereport only (mg/L)all year
E. coli, MTEC-MFmonthly geometric mean≤ 126 #/100mLApr–Oct
E. coli, MTEC-MFmonthly geometric mean≤ 630 #/100mLJan, Feb, Mar, Nov, Dec
E. coli, MTEC-MFmaximum 7-day geometric mean≤ 252 #/100mLApr–Oct
E. coli, MTEC-MFmaximum 7-day geometric mean≤ 1260 #/100mLJan, Feb, Mar, Nov, Dec
BOD, 5-day, percent removalminimum≥ 85 %all year
Solids, suspended percent removalminimum≥ 85 %all year
Duration of dischargemonthly totalreport only (d)all year
Oil and grease visualvaluereport only (Y=0;N=1)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/MT0030309 · MCP: https://passage-data.com/mcp