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City of Marengo

Sewage treatment plant, Marengo, Iowa. NPDES permit IA0047937 expired Jun 30, 2026; its limits still apply. Last 12 months: over a limit 27 times (last September 2026), 3 required values missing. Source: EPA ECHO, Oct 22, 2026.

Reports due
About 15 days after each period: form A monthly (25 values)
Last report on file
September 2026
Oct 2024 – Sep 2025
43 values over a limit, 8 required values missing, 0 of 12 reports late

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

All 27 values over a limit
Period endingParameterReportedLimitOver by
October 2025Oxygen, dissolved [DO], daily minimum.86≥ 5 mg/L83%
October 2025pH, daily minimum6.48≥ 6.5 SU—
November 2025Nitrogen, ammonia total [as N], 30-day average16.475≤ 14 mg/L18%
November 2025Oxygen, dissolved [DO], daily minimum3.29≥ 5 mg/L34%
December 2025Nitrogen, ammonia total [as N], 30-day average22.54≤ 14 mg/L61%
December 2025Nitrogen, ammonia total [as N], 30-day average40.08281≤ 38 lb/d5%
December 2025Nitrogen, ammonia total [as N], daily maximum26.2≤ 19 mg/L38%
December 2025Nitrogen, ammonia total [as N], daily maximum63.36732≤ 51 lb/d24%
December 2025Oxygen, dissolved [DO], daily minimum3.2≥ 5 mg/L36%
January 2026Oxygen, dissolved [DO], daily minimum4.12≥ 5 mg/L18%
March 2026Nitrogen, ammonia total [as N], 30-day average23.275≤ 14 mg/L66%
March 2026Nitrogen, ammonia total [as N], daily maximum25.9≤ 19 mg/L36%
April 2026Nitrogen, ammonia total [as N], 30-day average16.2475≤ 14 mg/L16%
April 2026Nitrogen, ammonia total [as N], 30-day average71.68037≤ 38 lb/d89%
April 2026Nitrogen, ammonia total [as N], daily maximum105.7036≤ 51 lb/d107%
April 2026Nitrogen, ammonia total [as N], daily maximum21.8≤ 19 mg/L15%
May 2026Oxygen, dissolved [DO], daily minimum2.03≥ 5 mg/L59%
June 2026Oxygen, dissolved [DO], daily minimum.28≥ 5 mg/L94%
July 2026Oxygen, dissolved [DO], daily minimum.4≥ 5 mg/L92%
August 2026Nitrogen, ammonia total [as N], 30-day average43.50641≤ 37 lb/d18%
August 2026Nitrogen, ammonia total [as N], daily maximum85.92935≤ 50 lb/d72%
August 2026Oxygen, dissolved [DO], daily minimum.92≥ 5 mg/L82%
September 2026BOD, carbonaceous [5 day, 20 C], 30-day average8878.169≤ 115 lb/d7620%
September 2026BOD, carbonaceous [5 day, 20 C], 7-day average44326.91≤ 183 lb/d24122%
September 2026Nitrogen, ammonia total [as N], 30-day average40815.54≤ 38 lb/d—
September 2026Nitrogen, ammonia total [as N], daily maximum203903.8≤ 51 lb/d—
September 2026Oxygen, dissolved [DO], daily minimum1.2≥ 5 mg/L76%

Limits in force (61)

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≤ 80 mg/Lall year
Solids, total suspended7-day average≤ 120 mg/Lall year
Solids, total suspended30-day average≤ 366 lb/dall year
Solids, total suspended7-day average≤ 549 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≤ 14 mg/LOct
Nitrogen, ammonia total [as N]30-day average≤ 14 mg/LJun
Nitrogen, ammonia total [as N]30-day average≤ 14 mg/LSep
Nitrogen, ammonia total [as N]30-day average≤ 12 mg/LJul
Nitrogen, ammonia total [as N]30-day average≤ 14 mg/LNov
Nitrogen, ammonia total [as N]30-day average≤ 12 mg/LAug
Nitrogen, ammonia total [as N]30-day average≤ 14 mg/LMar
Nitrogen, ammonia total [as N]30-day average≤ 14 mg/LApr
Nitrogen, ammonia total [as N]30-day average≤ 14 mg/LDec
Nitrogen, ammonia total [as N]30-day average≤ 14 mg/LMay
Nitrogen, ammonia total [as N]daily maximum≤ 19 mg/LOct
Nitrogen, ammonia total [as N]daily maximum≤ 19 mg/LJun
Nitrogen, ammonia total [as N]daily maximum≤ 19 mg/LSep
Nitrogen, ammonia total [as N]daily maximum≤ 19 mg/LJul
Nitrogen, ammonia total [as N]daily maximum≤ 19 mg/LNov
Nitrogen, ammonia total [as N]daily maximum≤ 19 mg/LAug
Nitrogen, ammonia total [as N]daily maximum≤ 19 mg/LMar
Nitrogen, ammonia total [as N]daily maximum≤ 19 mg/LApr
Nitrogen, ammonia total [as N]daily maximum≤ 19 mg/LDec
Nitrogen, ammonia total [as N]daily maximum≤ 19 mg/LMay
Nitrogen, ammonia total [as N]30-day average≤ 38 lb/dOct
Nitrogen, ammonia total [as N]30-day average≤ 38 lb/dJun
Nitrogen, ammonia total [as N]30-day average≤ 38 lb/dSep
Nitrogen, ammonia total [as N]30-day average≤ 37 lb/dJul
Nitrogen, ammonia total [as N]30-day average≤ 38 lb/dNov
Nitrogen, ammonia total [as N]30-day average≤ 37 lb/dAug
Nitrogen, ammonia total [as N]30-day average≤ 38 lb/dMar
Nitrogen, ammonia total [as N]30-day average≤ 38 lb/dApr
Nitrogen, ammonia total [as N]30-day average≤ 38 lb/dDec
Nitrogen, ammonia total [as N]30-day average≤ 38 lb/dMay
Nitrogen, ammonia total [as N]daily maximum≤ 51 lb/dOct
Nitrogen, ammonia total [as N]daily maximum≤ 51 lb/dJun
Nitrogen, ammonia total [as N]daily maximum≤ 51 lb/dSep
Nitrogen, ammonia total [as N]daily maximum≤ 50 lb/dJul
Nitrogen, ammonia total [as N]daily maximum≤ 51 lb/dNov
Nitrogen, ammonia total [as N]daily maximum≤ 50 lb/dAug
Nitrogen, ammonia total [as N]daily maximum≤ 51 lb/dMar
Nitrogen, ammonia total [as N]daily maximum≤ 51 lb/dApr
Nitrogen, ammonia total [as N]daily maximum≤ 51 lb/dDec
Nitrogen, ammonia total [as N]daily maximum≤ 51 lb/dMay
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≤ 115 lb/dall year
BOD, carbonaceous [5 day, 20 C]7-day average≤ 183 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/IA0047937 · MCP: https://passage-data.com/mcp