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Chelsea Sanitary District

Sewage treatment plant, Chelsea, Wisconsin. NPDES permit WI0035718 expired Dec 31, 2019; its limits still apply. Last 12 months: over a limit once (last December 2025), 22 required values missing, 4 of 22 reports late. Source: EPA ECHO, Oct 22, 2026.

Reports due
About 15 days after each period: outfall 001 form A monthly (7 values), outfall 701 form A monthly (4 values)
Last report on file
June 2026
Oct 2024 – Sep 2025
0 values over a limit, 24 required values missing, 8 of 24 reports late

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

Period endingParameterReportedLimitOver by
December 2025Phosphorus, total [as P], monthly average6.94≤ 6.4 mg/L8%

Limits in force (11)

ParameterStatisticLimitMonthsOutfall
Oxygen, dissolved [DO]daily minimum≥ 7 mg/Lall year001
pHdaily minimum≥ 6 SUall year001
pHdaily maximum≤ 9 SUall year001
Nitrogen, ammonia total [as N]daily maximumreport only (mg/L)all year001
Phosphorus, total [as P]monthly average≤ 6.4 mg/Lall year001
Flow, in conduit or thru treatment plantmonthly averagereport only (MGD)all year001
Flow, in conduit or thru treatment plantdaily maximumreport only (MGD)all year001
BOD, 5-day, 20 deg. Cmonthly averagereport only (mg/L)all year701
BOD, 5-day, 20 deg. Cdaily maximumreport only (mg/L)all year701
Solids, total suspendedmonthly averagereport only (mg/L)all year701
Solids, total suspendeddaily maximumreport only (mg/L)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

· Your permits on one board

On EPA ECHO: Facility report · DMR history

Your permit document is the final word. As JSON: /api/v1/permits/WI0035718 · MCP: https://passage-data.com/mcp