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City of Great Falls

Sewage treatment plant, Great Falls, Montana. NPDES permit MT0000442, in force until May 31, 2029. Last 12 months: no values over a limit. Source: EPA ECHO, Oct 22, 2026.

Reports due
About 28 days after each period: outfall 001 form A monthly (14 values), outfall 001 form A2 monthly (4 values), outfall 002 form A monthly (14 values), outfall 001 form S1 twice a year, outfall 001 form Y yearly, outfall 002 form S1 twice a year
Last report on file
September 2026
Oct 2024 – Sep 2025
0 values over a limit, 0 required values missing, 0 of 33 reports late

Limits in force (41)

ParameterStatisticLimitMonthsOutfall
Flow ratemonthly averagereport only (MGD)all year001
Flow ratedaily maximumreport only (MGD)all year001
pHdaily minimum≥ 6 SUall year001
pHdaily maximum≤ 9 SUall year001
Solids, total suspendedmonthly average≤ 30 mg/Lall year001
Solids, total suspendeddaily maximum≤ 45 mg/Lall year001
Solids, total suspendedmonthly average≤ 325 lb/dall year001
Solids, total suspendeddaily maximum≤ 900 lb/dall year001
Nitrogen, total [as N]monthly averagereport only (mg/L)Jul–Oct001
Nitrogen, total [as N]monthly averagereport only (lb/d)Jul–Oct001
Nitrogen, ammonia total [as N]monthly averagereport only (mg/L)all year001
Nitrogen, ammonia total [as N]daily maximumreport only (mg/L)all year001
Nitrogen, Kjeldahl, total [as N]monthly averagereport only (mg/L)Jul–Oct001
Nitrite + Nitrate total [as N]monthly averagereport only (mg/L)Jul–Oct001
Aluminum, dissolved [as Al]monthly averagereport only (mg/L)all year001
Aluminum, dissolved [as Al]daily maximumreport only (mg/L)all year001
N-Nitrosodimethylamine [NDMA]daily maximumreport only (ug/L)all year001
Chlorine, total residualmonthly average≤ .09999 mg/Lall year001
Chlorine, total residualdaily maximum≤ .16 mg/Lall year001
Haloacetic acids [HAA5]daily maximumreport only (mg/L)all year001
Solids, total dissolvedmonthly averagereport only (mg/L)all year001
Solids, total dissolveddaily maximumreport only (mg/L)all year001
Sulfatemonthly averagereport only (mg/L)all year001
Sulfatedaily maximumreport only (mg/L)all year001
Duration of dischargevaluereport only (d)all year001
Oil and grease visualvaluereport only (N=0;Y=1)all year001
Flow ratemonthly averagereport only (MGD)all year002
Flow ratedaily maximumreport only (MGD)all year002
pHdaily minimumreport only (SU)all year002
pHdaily maximumreport only (SU)all year002
Solids, total suspendedmonthly averagereport only (mg/L)all year002
Solids, total suspendeddaily maximumreport only (mg/L)all year002
Solids, total suspendedmonthly averagereport only (lb/d)all year002
Solids, total suspendeddaily maximumreport only (lb/d)all year002
Aluminum, dissolved [as Al]monthly averagereport only (mg/L)all year002
Aluminum, dissolved [as Al]daily maximumreport only (mg/L)all year002
N-Nitrosodimethylamine [NDMA]daily maximumreport only (ug/L)all year002
Chlorine, total residualmonthly averagereport only (mg/L)all year002
Chlorine, total residualdaily maximumreport only (mg/L)all year002
Duration of dischargevaluereport only (d)all year002
Oil and grease visualvaluereport only (N=0;Y=1)all year002

How strict are these limits?

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

Check this month's numbers Email me before each report is due

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On EPA ECHO: Facility report · DMR history

Your permit document is the final word. As JSON: /api/v1/permits/MT0000442 · MCP: https://passage-data.com/mcp