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Big Sand Lake/West Hertel WWTP

Sewage treatment plant, Hertel, Wisconsin. NPDES permit WI0062847 expired Apr 26, 2026; its limits still apply. Last 12 months: over a limit 3 times (last May 2026). Source: EPA ECHO, Oct 22, 2026.

Reports due
About 15 days after each period: form A quarterly (38 values)
Last report on file
June 2026
Oct 2024 – Sep 2025
3 values over a limit, 0 required values missing, 0 of 12 reports late

Last 12 months (Oct 1, 2025 – Sep 30, 2026)

Period endingParameterReportedLimitOver by
April 2026BOD, 5-day, 20 deg. C, weekly average31 mg/L≤ 30 mg/L3%
May 2026E. coli, daily maximum2000 MPN/100mL≤ 410 MPN/100mL388%
May 2026E. coli, monthly geometric mean360 MPN/100mL≤ 126 MPN/100mL186%

Limits in force (38)

ParameterStatisticLimitMonths
Temperature, water deg. fahrenheitmonthly averagereport only (deg F)all year
Temperature, water deg. fahrenheitdaily maximumreport only (deg F)all year
Oxygen, dissolved [DO]daily minimum≥ 4 mg/Lall year
BOD, 5-day, 20 deg. Cmonthly average≤ 20 mg/Lall year
BOD, 5-day, 20 deg. Cweekly average≤ 30 mg/Lall year
BOD, 5-day, 20 deg. Cmonthly average≤ 11.7 lb/dall year
BOD, 5-day, 20 deg. Cweekly average≤ 17.5 lb/dall year
BOD, 5-day, 20 deg. Cmonthly averagereport only (mg/L)all year
BOD, 5-day, 20 deg. Cmonthly averagereport only (lb/d)all year
pHminimum≥ 6 SUall year
pHmaximum≤ 9 SUall year
pHminimumreport only (SU)all year
pHmaximumreport only (SU)all year
Solids, total suspendedmonthly average≤ 20 mg/Lall year
Solids, total suspendedweekly average≤ 30 mg/Lall year
Solids, total suspendedmonthly average≤ 11.7 lb/dall year
Solids, total suspendedweekly average≤ 17.5 lb/dall year
Solids, total suspendedmonthly averagereport only (mg/L)all year
Solids, total suspendedmonthly averagereport only (lb/d)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
Phosphorus, total [as P]monthly averagereport only (mg/L)all year
Phosphorus, total [as P]monthly averagereport only (lb/d)all year
Phosphorus, total [as P]monthly averagereport only (mg/L)all year
Phosphorus, total [as P]monthly averagereport only (lb/d)all year
Hardness, total [as CaCO3]monthly averagereport only (mg/L)all year
Copper, total recoverablemonthly averagereport only (ug/L)all year
Copper, total recoverabledaily maximumreport only (ug/L)all year
Copper, total recoverablemonthly averagereport only (lb/d)all year
Copper, total recoverabledaily maximumreport only (lb/d)all year
Copper, total recoverablemonthly averagereport only (ug/L)all year
Flow, in conduit or thru treatment plantmonthly averagereport only (MGD)all year
Flow, in conduit or thru treatment plantmonthly averagereport only (MGD)all year
E. colimonthly geometric mean≤ 126 MPN/100mLMay–Sep
E. colidaily maximum≤ 410 MPN/100mLMay–Sep
BOD, 5-day, percent removalminimum % removal≥ 85 %all year
Solids, suspended percent removalminimum % removal≥ 85 %all year
Outfall observation,visual, y/n responsemonthly averagereport only (Y=0;N=1)all year

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/WI0062847 · MCP: https://passage-data.com/mcp