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City of Winthrop

Sewage treatment plant, Winthrop, Iowa. NPDES permit IA0032808, in force until Jan 31, 2031. Last 12 months: over a limit once (last June 2026). Source: EPA ECHO, Oct 22, 2026.

Reports due
About 15 days after each period: form A monthly (26 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

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

Period endingParameterReportedLimitOver by
June 2026Oxygen, dissolved [DO], daily minimum3.65≥ 4.9 mg/L26%

Limits in force (70)

ParameterStatisticLimitMonths
Oxygen, dissolved [DO]daily minimum≥ 4.9 mg/Lall year
BOD, 5-day, 20 deg. C30-day averagereport only (mg/L)all year
BOD, 5-day, 20 deg. Cdaily maximumreport only (mg/L)all year
BOD, 5-day, 20 deg. C30-day averagereport only (lb/d)all year
BOD, 5-day, 20 deg. Cdaily maximumreport only (lb/d)all year
pHdaily minimum≥ 6.5 SUall year
pHdaily maximum≤ 9 SUall year
pH30-day averagereport only (SU)all year
pHdaily maximumreport only (SU)all year
Solids, total suspended30-day average≤ 30 mg/Lall year
Solids, total suspended7-day average≤ 45 mg/Lall year
Solids, total suspended30-day average≤ 115 lb/dall year
Solids, total suspended7-day average≤ 173 lb/dall year
Solids, total suspended30-day averagereport only (mg/L)all year
Solids, total suspendeddaily maximumreport only (mg/L)all year
Solids, total suspended30-day averagereport only (lb/d)all year
Solids, total suspendeddaily maximumreport only (lb/d)all year
Nitrogen, ammonia total [as N]30-day average≤ 6.5 mg/LFeb
Nitrogen, ammonia total [as N]30-day average≤ 1.7 mg/LSep
Nitrogen, ammonia total [as N]30-day average≤ 2.5 mg/LOct
Nitrogen, ammonia total [as N]30-day average≤ 2.8 mg/LNov
Nitrogen, ammonia total [as N]30-day average≤ 1.6 mg/LJul
Nitrogen, ammonia total [as N]30-day average≤ 4 mg/LDec
Nitrogen, ammonia total [as N]30-day average≤ 5.6 mg/LJan
Nitrogen, ammonia total [as N]30-day average≤ 2.8 mg/LMay
Nitrogen, ammonia total [as N]30-day average≤ 4.1 mg/LMar
Nitrogen, ammonia total [as N]30-day average≤ 1.6 mg/LAug
Nitrogen, ammonia total [as N]30-day average≤ 2.1 mg/LJun
Nitrogen, ammonia total [as N]30-day average≤ 2.5 mg/LApr
Nitrogen, ammonia total [as N]daily maximum≤ 8.7 mg/LFeb
Nitrogen, ammonia total [as N]daily maximum≤ 2.8 mg/LSep
Nitrogen, ammonia total [as N]daily maximum≤ 2.8 mg/LOct
Nitrogen, ammonia total [as N]daily maximum≤ 2.8 mg/LNov
Nitrogen, ammonia total [as N]daily maximum≤ 3.4 mg/LJul
Nitrogen, ammonia total [as N]daily maximum≤ 4 mg/LDec
Nitrogen, ammonia total [as N]daily maximum≤ 20.2 mg/LJan
Nitrogen, ammonia total [as N]daily maximum≤ 3.4 mg/LMay
Nitrogen, ammonia total [as N]daily maximum≤ 4.1 mg/LMar
Nitrogen, ammonia total [as N]daily maximum≤ 2.8 mg/LAug
Nitrogen, ammonia total [as N]daily maximum≤ 3.4 mg/LJun
Nitrogen, ammonia total [as N]daily maximum≤ 4.9 mg/LApr
Nitrogen, ammonia total [as N]30-day average≤ 17.2 lb/dFeb
Nitrogen, ammonia total [as N]30-day average≤ 4.6 lb/dSep
Nitrogen, ammonia total [as N]30-day average≤ 6.8 lb/dOct
Nitrogen, ammonia total [as N]30-day average≤ 10.1 lb/dNov
Nitrogen, ammonia total [as N]30-day average≤ 4.4 lb/dJul
Nitrogen, ammonia total [as N]30-day average≤ 10.8 lb/dDec
Nitrogen, ammonia total [as N]30-day average≤ 14.9 lb/dJan
Nitrogen, ammonia total [as N]30-day average≤ 7.6 lb/dMay
Nitrogen, ammonia total [as N]30-day average≤ 14.8 lb/dMar
Nitrogen, ammonia total [as N]30-day average≤ 4.2 lb/dAug
Nitrogen, ammonia total [as N]30-day average≤ 5.7 lb/dJun
Nitrogen, ammonia total [as N]30-day average≤ 6.7 lb/dApr
Nitrogen, ammonia total [as N]daily maximum≤ 32.5 lb/dFeb
Nitrogen, ammonia total [as N]daily maximum≤ 10.3 lb/dSep
Nitrogen, ammonia total [as N]daily maximum≤ 10.3 lb/dOct
Nitrogen, ammonia total [as N]daily maximum≤ 10.3 lb/dNov
Nitrogen, ammonia total [as N]daily maximum≤ 12.4 lb/dJul
Nitrogen, ammonia total [as N]daily maximum≤ 15 lb/dDec
Nitrogen, ammonia total [as N]daily maximum≤ 76.6 lb/dJan
Nitrogen, ammonia total [as N]daily maximum≤ 12.4 lb/dMay
Nitrogen, ammonia total [as N]daily maximum≤ 15.1 lb/dMar
Nitrogen, ammonia total [as N]daily maximum≤ 10.3 lb/dAug
Nitrogen, ammonia total [as N]daily maximum≤ 12.4 lb/dJun
Nitrogen, ammonia total [as N]daily maximum≤ 18.2 lb/dApr
E. coligeometric mean≤ 630 #/100mLMar–Nov
BOD, carbonaceous [5 day, 20 C]30-day average≤ 25 mg/Lall year
BOD, carbonaceous [5 day, 20 C]7-day average≤ 40 mg/Lall year
BOD, carbonaceous [5 day, 20 C]30-day average≤ 96 lb/dall year
BOD, carbonaceous [5 day, 20 C]7-day average≤ 154 lb/dall year

How strict are these limits?

Cited limits by parameter: Iowa's rules and the federal ones.

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On EPA ECHO: Facility report · DMR history

Your permit document is the final word. As JSON: /api/v1/permits/IA0032808 · MCP: https://passage-data.com/mcp