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City of Solon

Sewage treatment plant, Solon, Iowa. NPDES permit IA0036978, in force until May 31, 2027. Last 12 months: over a limit 7 times (last September 2026). Source: EPA ECHO, Oct 22, 2026.

Reports due
About 15 days after each period: form A monthly (40 values)
Renewal application due
Dec 2, 2026 · 180 days before expiry; your permit may set another date
Last report on file
September 2026
Oct 2024 – Sep 2025
7 values over a limit, 1 required value missing, 0 of 12 reports late

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

Period endingParameterReportedLimitOver by
October 2025E. coli, geometric mean184.9985≤ 126 #/100mL47%
December 2025BOD, carbonaceous [5 day, 20 C], 30-day average182.9448≤ 142 lb/d29%
December 2025BOD, carbonaceous [5 day, 20 C], 30-day average43.061≤ 25 mg/L72%
December 2025BOD, carbonaceous [5 day, 20 C], 7-day average211.92≤ 40 mg/L430%
December 2025BOD, carbonaceous [5 day, 20 C], 7-day average902.1494≤ 227 lb/d297%
February 2026Phosphorus, total [as P], 30-day average14.8452≤ 13.3 lb/d12%
September 2026Phosphorus, total [as P], 30-day average17.04437≤ 13.3 lb/d28%

Limits in force (88)

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≤ 170 lb/dall year
Solids, total suspended7-day average≤ 255 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≤ 1.6 mg/LOct
Nitrogen, ammonia total [as N]30-day average≤ 2.3 mg/LNov
Nitrogen, ammonia total [as N]30-day average≤ 1.7 mg/LMay
Nitrogen, ammonia total [as N]30-day average≤ 3.4 mg/LJan
Nitrogen, ammonia total [as N]30-day average≤ 4 mg/LFeb
Nitrogen, ammonia total [as N]30-day average≤ 1.1 mg/LSep
Nitrogen, ammonia total [as N]30-day average≤ 1.5 mg/LApr
Nitrogen, ammonia total [as N]30-day average≤ 2.5 mg/LDec
Nitrogen, ammonia total [as N]30-day average≤ 3.4 mg/LMar
Nitrogen, ammonia total [as N]30-day average≤ 1.3 mg/LJun
Nitrogen, ammonia total [as N]30-day average≤ 1 mg/LJul
Nitrogen, ammonia total [as N]30-day average≤ 1 mg/LAug
Nitrogen, ammonia total [as N]daily maximum≤ 6.4 mg/LOct
Nitrogen, ammonia total [as N]daily maximum≤ 9.8 mg/LNov
Nitrogen, ammonia total [as N]daily maximum≤ 6.4 mg/LMay
Nitrogen, ammonia total [as N]daily maximum≤ 15.2 mg/LJan
Nitrogen, ammonia total [as N]daily maximum≤ 14.2 mg/LFeb
Nitrogen, ammonia total [as N]daily maximum≤ 3.9 mg/LSep
Nitrogen, ammonia total [as N]daily maximum≤ 9.5 mg/LApr
Nitrogen, ammonia total [as N]daily maximum≤ 14 mg/LDec
Nitrogen, ammonia total [as N]daily maximum≤ 14.5 mg/LMar
Nitrogen, ammonia total [as N]daily maximum≤ 4.3 mg/LJun
Nitrogen, ammonia total [as N]daily maximum≤ 3.3 mg/LJul
Nitrogen, ammonia total [as N]daily maximum≤ 3.3 mg/LAug
Nitrogen, ammonia total [as N]30-day average≤ 8.8 lb/dOct
Nitrogen, ammonia total [as N]30-day average≤ 13.2 lb/dNov
Nitrogen, ammonia total [as N]30-day average≤ 9.9 lb/dMay
Nitrogen, ammonia total [as N]30-day average≤ 19.3 lb/dJan
Nitrogen, ammonia total [as N]30-day average≤ 22.4 lb/dFeb
Nitrogen, ammonia total [as N]30-day average≤ 6 lb/dSep
Nitrogen, ammonia total [as N]30-day average≤ 8.6 lb/dApr
Nitrogen, ammonia total [as N]30-day average≤ 14 lb/dDec
Nitrogen, ammonia total [as N]30-day average≤ 19.3 lb/dMar
Nitrogen, ammonia total [as N]30-day average≤ 7.4 lb/dJun
Nitrogen, ammonia total [as N]30-day average≤ 5.7 lb/dJul
Nitrogen, ammonia total [as N]30-day average≤ 5.4 lb/dAug
Nitrogen, ammonia total [as N]daily maximum≤ 28.9 lb/dOct
Nitrogen, ammonia total [as N]daily maximum≤ 43.7 lb/dNov
Nitrogen, ammonia total [as N]daily maximum≤ 30.1 lb/dMay
Nitrogen, ammonia total [as N]daily maximum≤ 74.9 lb/dJan
Nitrogen, ammonia total [as N]daily maximum≤ 80.5 lb/dFeb
Nitrogen, ammonia total [as N]daily maximum≤ 18.1 lb/dSep
Nitrogen, ammonia total [as N]daily maximum≤ 44.2 lb/dApr
Nitrogen, ammonia total [as N]daily maximum≤ 62.4 lb/dDec
Nitrogen, ammonia total [as N]daily maximum≤ 66.9 lb/dMar
Nitrogen, ammonia total [as N]daily maximum≤ 20.4 lb/dJun
Nitrogen, ammonia total [as N]daily maximum≤ 15.3 lb/dJul
Nitrogen, ammonia total [as N]daily maximum≤ 14.7 lb/dAug
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 average≤ 13.3 lb/dall year
Phosphorus, total [as P]daily maximum≤ 21.8 lb/dall year
Chloride [as Cl]30-day average≤ 389 mg/Lall year
Chloride [as Cl]daily maximum≤ 629 mg/Lall year
Chloride [as Cl]30-day average≤ 2204 lb/dall year
Chloride [as Cl]daily maximum≤ 3566 lb/dall year
Chlorine, total residual30-day average≤ .242 mg/Lall year
Chlorine, total residualdaily maximum≤ .319 mg/Lall year
Chlorine, total residual30-day average≤ 1.37 lb/dall year
Chlorine, total residualdaily maximum≤ 1.81 lb/dall year
E. coligeometric mean≤ 126 #/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≤ 142 lb/dall year
BOD, carbonaceous [5 day, 20 C]7-day average≤ 227 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/IA0036978 · MCP: https://passage-data.com/mcp