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City of Carroll

Sewage treatment plant, major discharger, Carroll, Iowa. NPDES permit IA0021377, in force until Aug 31, 2027. 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 (50 values)
Renewal application due
Mar 4, 2027 · 180 days before expiry; your permit may set another date
Last report on file
August 2026
Oct 2024 – Sep 2025
0 values over a limit, 0 required values missing, 0 of 12 reports late

Limits in force (98)

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≤ 1051 lb/dall year
Solids, total suspended7-day average≤ 1576 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, 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 mg/LJul
Nitrogen, ammonia total [as N]30-day average≤ 1.4 mg/LJun
Nitrogen, ammonia total [as N]30-day average≤ 1.8 mg/LMay
Nitrogen, ammonia total [as N]30-day average≤ 1.6 mg/LApr
Nitrogen, ammonia total [as N]30-day average≤ 1.6 mg/LOct
Nitrogen, ammonia total [as N]30-day average≤ 2.6 mg/LDec
Nitrogen, ammonia total [as N]30-day average≤ 3.5 mg/LJan
Nitrogen, ammonia total [as N]30-day average≤ 1.1 mg/LSep
Nitrogen, ammonia total [as N]30-day average≤ 3.5 mg/LMar
Nitrogen, ammonia total [as N]30-day average≤ 4.1 mg/LFeb
Nitrogen, ammonia total [as N]30-day average≤ 2.4 mg/LNov
Nitrogen, ammonia total [as N]30-day average≤ 1 mg/LAug
Nitrogen, ammonia total [as N]daily maximum≤ 5 mg/LJul
Nitrogen, ammonia total [as N]daily maximum≤ 7.3 mg/LJun
Nitrogen, ammonia total [as N]daily maximum≤ 12.1 mg/LMay
Nitrogen, ammonia total [as N]daily maximum≤ 15.7 mg/LApr
Nitrogen, ammonia total [as N]daily maximum≤ 12.3 mg/LOct
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≤ 6.6 mg/LSep
Nitrogen, ammonia total [as N]daily maximum≤ 14.7 mg/LMar
Nitrogen, ammonia total [as N]daily maximum≤ 14.2 mg/LFeb
Nitrogen, ammonia total [as N]daily maximum≤ 14.7 mg/LNov
Nitrogen, ammonia total [as N]daily maximum≤ 5.6 mg/LAug
Nitrogen, ammonia total [as N]30-day average≤ 35.6 lb/dJul
Nitrogen, ammonia total [as N]30-day average≤ 46.4 lb/dJun
Nitrogen, ammonia total [as N]30-day average≤ 61.6 lb/dMay
Nitrogen, ammonia total [as N]30-day average≤ 54 lb/dApr
Nitrogen, ammonia total [as N]30-day average≤ 55.2 lb/dOct
Nitrogen, ammonia total [as N]30-day average≤ 87.7 lb/dDec
Nitrogen, ammonia total [as N]30-day average≤ 120.7 lb/dJan
Nitrogen, ammonia total [as N]30-day average≤ 37.5 lb/dSep
Nitrogen, ammonia total [as N]30-day average≤ 120.7 lb/dMar
Nitrogen, ammonia total [as N]30-day average≤ 140.1 lb/dFeb
Nitrogen, ammonia total [as N]30-day average≤ 82.3 lb/dNov
Nitrogen, ammonia total [as N]30-day average≤ 33.8 lb/dAug
Nitrogen, ammonia total [as N]daily maximum≤ 140.1 lb/dJul
Nitrogen, ammonia total [as N]daily maximum≤ 210.2 lb/dJun
Nitrogen, ammonia total [as N]daily maximum≤ 357.3 lb/dMay
Nitrogen, ammonia total [as N]daily maximum≤ 550 lb/dApr
Nitrogen, ammonia total [as N]daily maximum≤ 409.8 lb/dOct
Nitrogen, ammonia total [as N]daily maximum≤ 559.1 lb/dDec
Nitrogen, ammonia total [as N]daily maximum≤ 532 lb/dJan
Nitrogen, ammonia total [as N]daily maximum≤ 192.7 lb/dSep
Nitrogen, ammonia total [as N]daily maximum≤ 514.5 lb/dMar
Nitrogen, ammonia total [as N]daily maximum≤ 497.3 lb/dFeb
Nitrogen, ammonia total [as N]daily maximum≤ 514.5 lb/dNov
Nitrogen, ammonia total [as N]daily maximum≤ 161.1 lb/dAug
Nitrogen, Kjeldahl, total [as N]30-day average≤ 1940 lb/dall year
Nitrogen, Kjeldahl, total [as N]daily maximum≤ 3175 lb/dall year
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
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
Copper, total [as Cu]30-day average≤ .01687 mg/Lall year
Copper, total [as Cu]daily maximum≤ .0269 mg/Lall year
Copper, total [as Cu]30-day average≤ .5908 lb/dall year
Copper, total [as Cu]daily maximum≤ .9422 lb/dall year
E. coligeometric mean≤ 126 #/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≤ 876 lb/dall year
BOD, carbonaceous [5 day, 20 C]7-day average≤ 1401 lb/dall year

New limits from Aug 1, 2027

ParameterNew limitNew or tighterMedian, last 12 months× new limit
Chloride [as Cl], 30-day average13614 lb/dnew——
Chloride [as Cl], 30-day average389 mg/Lnew——
Chloride [as Cl], daily maximum629 mg/Lnew——
Chloride [as Cl], daily maximum22027 lb/dnew——
Selenium, total [as Se], 30-day average0.1751 lb/dnew——
Selenium, total [as Se], 30-day average0.005 mg/Lnew——
Selenium, total [as Se], daily maximum0.0193 mg/Lnew——
Selenium, total [as Se], daily maximum0.676 lb/dnew——
Thallium, total [as Tl], 30-day average0.02531 lb/dnew——
Thallium, total [as Tl], 30-day average0.001133 mg/Lnew——
Thallium, total [as Tl], daily maximum0.598 mg/Lnew——
Thallium, total [as Tl], daily maximum20.95 lb/dnew——

How strict are these limits?

Cited limits by parameter: Iowa'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/IA0021377 · MCP: https://passage-data.com/mcp