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Polson- City of

Sewage treatment plant, Polson, Montana. NPDES permit MT0020559 expired Aug 31, 2024; 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 (37 values)
Last report on file
August 2026
Oct 2024 – Sep 2025
0 values over a limit, 0 required values missing, 0 of 12 reports late

Limits in force (37)

ParameterStatisticLimitMonths
Temperature, water deg. centigradedaily minimumreport only (deg C)all year
Temperature, water deg. centigradedaily maximumreport only (deg C)all year
Oxygen, dissolved [DO]30-day averagereport only (mg/L)all year
Oxygen, dissolved [DO]daily maximumreport only (mg/L)all year
BOD, 5-day, 20 deg. C30-day average≤ 30 mg/Lall year
BOD, 5-day, 20 deg. C7-day average≤ 45 mg/Lall year
BOD, 5-day, 20 deg. C30-day averagereport only (mg/L)all year
BOD, 5-day, 20 deg. C7-day averagereport only (mg/L)all year
pHminimum≥ 6.5 SUall year
pHmaximum≤ 9 SUall year
Solids, total suspended30-day average≤ 30 mg/Lall year
Solids, total suspended7-day average≤ 45 mg/Lall year
Solids, total suspended30-day averagereport only (mg/L)all year
Solids, total suspended7-day averagereport only (mg/L)all year
Oil & Greasedaily maximum≤ 10 mg/Lall year
Nitrogen, total [as N]30-day averagereport only (mg/L)all year
Nitrogen, total [as N]daily maximumreport only (mg/L)all year
Nitrogen, ammonia total [as N]30-day averagereport only (mg/L)all year
Nitrogen, ammonia total [as N]daily maximumreport only (mg/L)all year
Nitrogen, Kjeldahl, total [as N]30-day averagereport only (mg/L)all year
Nitrogen, Kjeldahl, total [as N]daily maximumreport only (mg/L)all year
Nitrite + Nitrate total [as N]30-day averagereport only (mg/L)all year
Nitrite + Nitrate total [as N]daily maximumreport only (mg/L)all year
Phosphorus, total [as P]30-day averagereport only (mg/L)all year
Phosphorus, total [as P]daily maximumreport only (mg/L)all year
Floating solids, waste or visible foam-visualinstantaneous maximumreport only (N=0;Y=1)all year
Chlorine, total residual30-day average≤ .05 mg/Lall year
Chlorine, total residualdaily maximum≤ .05 mg/Lall year
E. coli30-day average≤ 252 #/100mLall year
E. colidaily maximum≤ 126 #/100mLall year
Coliform, fecal general30-day average≤ 400 #/100mLall year
Coliform, fecal generaldaily maximum≤ 200 #/100mLall year
BOD, 5-day, percent removalmonthly average minimum≥ 85 %all year
Solids, suspended percent removalmonthly average minimum≥ 85 %all year
Flow, total30-day average≤ .92 MGDall year
Flow, totaldaily maximumreport only (MGD)all year
Oil and grease visualinstantaneous maximumreport only (N=0;Y=1)all year

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/MT0020559 · MCP: https://passage-data.com/mcp