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City of Grinnell

Sewage treatment plant, major discharger, Grinnell, Iowa. NPDES permit IA0031186, in force until Nov 30, 2029. Last 12 months: no values over a limit. Source: EPA ECHO, Oct 22, 2026.

Reports due
About 15 days after each period: form A monthly (40 values)
Last report on file
September 2026
Oct 2024 – Sep 2025
0 values over a limit, 0 required values missing, 0 of 12 reports late

Limits in force (84)

ParameterStatisticLimitMonths
Oxygen, dissolved [DO]daily minimum≥ 5 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≤ 1060 lb/dall year
Solids, total suspended7-day average≤ 1590 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, total [as N]30-day averagereport only (mg/L)all year
Nitrogen, total [as N]daily maximumreport only (mg/L)all year
Nitrogen, total [as N]30-day averagereport only (lb/d)all year
Nitrogen, total [as N]daily maximumreport only (lb/d)all year
Nitrogen, ammonia total [as N]30-day average≤ 1.5 mg/LApr
Nitrogen, ammonia total [as N]30-day average≤ 1 mg/LJul
Nitrogen, ammonia total [as N]30-day average≤ 1.1 mg/LSep
Nitrogen, ammonia total [as N]30-day average≤ 1.7 mg/LMay
Nitrogen, ammonia total [as N]30-day average≤ 4 mg/LFeb
Nitrogen, ammonia total [as N]30-day average≤ 3.4 mg/LMar
Nitrogen, ammonia total [as N]30-day average≤ 2.3 mg/LNov
Nitrogen, ammonia total [as N]30-day average≤ 2.5 mg/LDec
Nitrogen, ammonia total [as N]30-day average≤ 3.4 mg/LJan
Nitrogen, ammonia total [as N]30-day average≤ 1 mg/LAug
Nitrogen, ammonia total [as N]30-day average≤ 1.3 mg/LJun
Nitrogen, ammonia total [as N]30-day average≤ 1.6 mg/LOct
Nitrogen, ammonia total [as N]daily maximum≤ 15.7 mg/LApr
Nitrogen, ammonia total [as N]daily maximum≤ 17.6 mg/LJul
Nitrogen, ammonia total [as N]daily maximum≤ 16.5 mg/LSep
Nitrogen, ammonia total [as N]daily maximum≤ 15.2 mg/LMay
Nitrogen, ammonia total [as N]daily maximum≤ 14.2 mg/LFeb
Nitrogen, ammonia total [as N]daily maximum≤ 14.7 mg/LMar
Nitrogen, ammonia total [as N]daily maximum≤ 14.7 mg/LNov
Nitrogen, ammonia total [as N]daily maximum≤ 16 mg/LDec
Nitrogen, ammonia total [as N]daily maximum≤ 15.2 mg/LJan
Nitrogen, ammonia total [as N]daily maximum≤ 16.2 mg/LAug
Nitrogen, ammonia total [as N]daily maximum≤ 14.4 mg/LJun
Nitrogen, ammonia total [as N]daily maximum≤ 15.7 mg/LOct
Nitrogen, ammonia total [as N]30-day average≤ 53.8 lb/dApr
Nitrogen, ammonia total [as N]30-day average≤ 35.5 lb/dJul
Nitrogen, ammonia total [as N]30-day average≤ 37.3 lb/dSep
Nitrogen, ammonia total [as N]30-day average≤ 61.4 lb/dMay
Nitrogen, ammonia total [as N]30-day average≤ 139.6 lb/dFeb
Nitrogen, ammonia total [as N]30-day average≤ 120.3 lb/dMar
Nitrogen, ammonia total [as N]30-day average≤ 82 lb/dNov
Nitrogen, ammonia total [as N]30-day average≤ 87.4 lb/dDec
Nitrogen, ammonia total [as N]30-day average≤ 120.3 lb/dJan
Nitrogen, ammonia total [as N]30-day average≤ 33.7 lb/dAug
Nitrogen, ammonia total [as N]30-day average≤ 46.2 lb/dJun
Nitrogen, ammonia total [as N]30-day average≤ 55 lb/dOct
Nitrogen, ammonia total [as N]daily maximum≤ 554.7 lb/dApr
Nitrogen, ammonia total [as N]daily maximum≤ 621.2 lb/dJul
Nitrogen, ammonia total [as N]daily maximum≤ 582.6 lb/dSep
Nitrogen, ammonia total [as N]daily maximum≤ 536.6 lb/dMay
Nitrogen, ammonia total [as N]daily maximum≤ 501.6 lb/dFeb
Nitrogen, ammonia total [as N]daily maximum≤ 518.9 lb/dMar
Nitrogen, ammonia total [as N]daily maximum≤ 518.9 lb/dNov
Nitrogen, ammonia total [as N]daily maximum≤ 563.9 lb/dDec
Nitrogen, ammonia total [as N]daily maximum≤ 536.6 lb/dJan
Nitrogen, ammonia total [as N]daily maximum≤ 573.2 lb/dAug
Nitrogen, ammonia total [as N]daily maximum≤ 510.2 lb/dJun
Nitrogen, ammonia total [as N]daily maximum≤ 554.7 lb/dOct
Nitrogen, Kjeldahl, total [as N]30-day averagereport only (mg/L)all year
Nitrogen, Kjeldahl, total [as N]daily maximumreport only (mg/L)all year
Nitrogen, Kjeldahl, total [as N]30-day averagereport only (lb/d)all year
Nitrogen, Kjeldahl, total [as N]daily maximumreport only (lb/d)all year
Phosphorus, total [as P]30-day averagereport only (mg/L)all year
Phosphorus, total [as P]daily maximumreport only (mg/L)all year
Phosphorus, total [as P]30-day averagereport only (lb/d)all year
Phosphorus, total [as P]daily maximumreport only (lb/d)all year
E. coligeometric mean≤ 630 #/100mLMar–Nov
Toxicity [acute], Ceriodaphnia dubiadaily maximum≤ 1 N=0;Y=1all year
Toxicity [acute], Pimephales promelas [Fathead Minnow]daily maximum≤ 1 N=0;Y=1all year
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≤ 883 lb/dall year
BOD, carbonaceous [5 day, 20 C]7-day average≤ 1413 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/IA0031186 · MCP: https://passage-data.com/mcp