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City of Onawa

Sewage treatment plant, Onawa, Iowa. NPDES permit IA0036145 expired Apr 27, 2008; its limits still apply. Last 12 months: over a limit 26 times (last August 2026). Source: EPA ECHO, Oct 22, 2026.

Reports due
About 15 days after each period: form A monthly (22 values)
Last report on file
August 2026
Oct 2024 – Sep 2025
5 values over a limit, 0 required values missing, 0 of 12 reports late

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

All 26 values over a limit
Period endingParameterReportedLimitOver by
December 2025BOD, carbonaceous [5 day, 20 C], 30-day average65.36≤ 25 mg/L161%
December 2025BOD, carbonaceous [5 day, 20 C], 7-day average81.4≤ 40 mg/L104%
December 2025Solids, total suspended, 30-day average104.42≤ 30 mg/L248%
December 2025Solids, total suspended, 7-day average156≤ 45 mg/L247%
January 2026BOD, carbonaceous [5 day, 20 C], 30-day average57.625≤ 25 mg/L131%
January 2026BOD, carbonaceous [5 day, 20 C], 7-day average97≤ 40 mg/L143%
January 2026Solids, total suspended, 30-day average108.925≤ 30 mg/L263%
January 2026Solids, total suspended, 7-day average177≤ 45 mg/L293%
February 2026BOD, carbonaceous [5 day, 20 C], 30-day average52.825≤ 25 mg/L111%
February 2026BOD, carbonaceous [5 day, 20 C], 7-day average98.55≤ 40 mg/L146%
February 2026Solids, total suspended, 30-day average85.175≤ 30 mg/L184%
February 2026Solids, total suspended, 7-day average143≤ 45 mg/L218%
March 2026BOD, carbonaceous [5 day, 20 C], 30-day average25.565≤ 25 mg/L2%
March 2026BOD, carbonaceous [5 day, 20 C], 7-day average56.2≤ 40 mg/L41%
March 2026Solids, total suspended, 30-day average54.04≤ 30 mg/L80%
March 2026Solids, total suspended, 7-day average80≤ 45 mg/L78%
April 2026BOD, carbonaceous [5 day, 20 C], 30-day average25.975≤ 25 mg/L4%
April 2026Solids, total suspended, 30-day average83.05≤ 30 mg/L177%
April 2026Solids, total suspended, 7-day average177≤ 45 mg/L293%
May 2026Solids, total suspended, 30-day average167.025≤ 30 mg/L457%
May 2026Solids, total suspended, 30-day average272.6017≤ 258 lb/d6%
May 2026Solids, total suspended, 7-day average478≤ 45 mg/L962%
May 2026Solids, total suspended, 7-day average768.3459≤ 387 lb/d99%
July 2026Solids, total suspended, 30-day average38.275≤ 30 mg/L28%
July 2026Solids, total suspended, 7-day average75.9≤ 45 mg/L69%
August 2026Solids, total suspended, 7-day average51≤ 45 mg/L13%

Limits in force (22)

ParameterStatisticLimitMonths
pHdaily minimum≥ 6 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≤ 258 lb/dall year
Solids, total suspended7-day average≤ 387 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
Toxicity [acute], Ceriodaphnia dubia30-day average≤ 1 N=0;Y=1all year
Toxicity [acute], Pimephales promelas [Fathead Minnow]30-day average≤ 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≤ 215 lb/dall year
BOD, carbonaceous [5 day, 20 C]7-day average≤ 344 lb/dall year
BOD, carbonaceous [5 day, 20 C]30-day averagereport only (mg/L)all year
BOD, carbonaceous [5 day, 20 C]daily maximumreport only (mg/L)all year
BOD, carbonaceous [5 day, 20 C]30-day averagereport only (lb/d)all year
BOD, carbonaceous [5 day, 20 C]daily maximumreport only (lb/d)all 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/IA0036145 · MCP: https://passage-data.com/mcp