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City of Libby

Sewage treatment plant, Libby, Montana. NPDES permit MT0030341 expired Jul 31, 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 (14 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 (14)

ParameterStatisticLimitMonths
Flow ratemonthly averagereport only (MGD)all year
Flow ratedaily maximumreport only (MGD)all year
pHminimum≥ 6 SUall year
pHmaximum≤ 9 SUall year
Solids, total suspendedmonthly average≤ 30 mg/Lall year
Solids, total suspendeddaily maximum≤ 45 mg/Lall year
Solids, total suspendedmonthly average≤ 22.5 lb/dall year
Solids, total suspendeddaily maximum≤ 123.8 lb/dall year
Aluminum, dissolved [as Al]monthly average≤ 1 mg/Lall year
Aluminum, dissolved [as Al]daily maximum≤ 1.5 mg/Lall year
Aluminum, dissolved [as Al]monthly average≤ 1.44 lb/dall year
Aluminum, dissolved [as Al]daily maximum≤ 2.16 lb/dall year
Chlorine, total residualmonthly averagereport only (mg/L)all year
Chlorine, total residualdaily maximum≤ .1 mg/Lall 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/MT0030341 · MCP: https://passage-data.com/mcp