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Colby City WWTF

Sewage treatment plant, Colby, Wisconsin. NPDES permit WI0023655 expired Sep 30, 2025; its limits still apply. Last 12 months: no values over a limit, 35 required values missing. Source: EPA ECHO, Oct 22, 2026.

Reports due
About 21 days after each period: outfall 001 form A monthly (11 values), outfall 001 form Q quarterly (2 values), outfall 701 form A monthly (6 values)
Last report on file
June 2026
Oct 2024 – Sep 2025
0 values over a limit, 12 required values missing, 1 of 28 reports late

Limits in force (19)

ParameterStatisticLimitMonthsOutfall
Oxygen, dissolved [DO]daily minimum≥ 4 mg/Lall year001
BOD, 5-day, 20 deg. Cmonthly average≤ 15 mg/Lall year001
BOD, 5-day, 20 deg. Cdaily maximum≤ 30 mg/Lall year001
pHdaily minimum≥ 6 SUall year001
pHdaily maximum≤ 9 SUall year001
Solids, total suspendedmonthly average≤ 20 mg/Lall year001
Solids, total suspendeddaily maximum≤ 30 mg/Lall year001
Hardness, total [as CaCO3]quarterly maximumreport only (mg/L)all year001
Chloride [as Cl]quarterly maximumreport only (mg/L)all year001
Copper, total recoverablemonthly averagereport only (lb/d)all year001
Copper, total recoverablemonthly maximumreport only (lb/d)all year001
Flow, in conduit or thru treatment plantmonthly averagereport only (MGD)all year001
Flow, in conduit or thru treatment plantmonthly maximumreport only (MGD)all year001
BOD, 5-day, 20 deg. Cmonthly averagereport only (mg/L)all year701
BOD, 5-day, 20 deg. Cmonthly maximumreport only (mg/L)all year701
Solids, total suspendedmonthly averagereport only (mg/L)all year701
Solids, total suspendedmonthly maximumreport only (mg/L)all year701
Flow, in conduit or thru treatment plantmonthly averagereport only (MGD)all year701
Flow, in conduit or thru treatment plantmonthly maximumreport only (MGD)all year701

How strict are these limits?

Cited limits by parameter: Wisconsin'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/WI0023655 · MCP: https://passage-data.com/mcp