Passage Data · Check a report · Use it from your AI

City of Mount Vernon

Sewage treatment plant, major discharger, Mount Vernon, Iowa. NPDES permit IA0023710, in force until Sep 30, 2030. Last 12 months: over a limit 6 times (last July 2026). Source: EPA ECHO, Oct 22, 2026.

Reports due
About 15 days after each period: form A monthly (48 values)
Last report on file
August 2026
Oct 2024 – Sep 2025
3 values over a limit, 4 required values missing, 2 of 12 reports late

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

Period endingParameterReportedLimitOver by
November 2025Chloride [as Cl], 30-day average390≤ 389 mg/L0%
December 2025Chloride [as Cl], 30-day average420≤ 389 mg/L8%
June 2026Chloride [as Cl], 30-day average420≤ 389 mg/L8%
July 2026Chloride [as Cl], 30-day average410≤ 389 mg/L5%
July 2026pH, daily minimum5.3≥ 6.5 SU—
July 2026pH, daily maximum9.3≤ 9 SU—

Limits in force (92)

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≤ 359 lb/dall year
Solids, total suspended7-day average≤ 539 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≤ 1.7 mg/LMay
Nitrogen, ammonia total [as N]30-day average≤ 1.1 mg/LSep
Nitrogen, ammonia total [as N]30-day average≤ 2.5 mg/LDec
Nitrogen, ammonia total [as N]30-day average≤ 1.5 mg/LApr
Nitrogen, ammonia total [as N]30-day average≤ 4 mg/LFeb
Nitrogen, ammonia total [as N]30-day average≤ 1 mg/LAug
Nitrogen, ammonia total [as N]30-day average≤ 1.6 mg/LOct
Nitrogen, ammonia total [as N]30-day average≤ 3.4 mg/LJan
Nitrogen, ammonia total [as N]30-day average≤ 3.4 mg/LMar
Nitrogen, ammonia total [as N]30-day average≤ 1 mg/LJul
Nitrogen, ammonia total [as N]30-day average≤ 2.3 mg/LNov
Nitrogen, ammonia total [as N]30-day average≤ 1.3 mg/LJun
Nitrogen, ammonia total [as N]daily maximum≤ 15.2 mg/LMay
Nitrogen, ammonia total [as N]daily maximum≤ 16.5 mg/LSep
Nitrogen, ammonia total [as N]daily maximum≤ 16 mg/LDec
Nitrogen, ammonia total [as N]daily maximum≤ 15.7 mg/LApr
Nitrogen, ammonia total [as N]daily maximum≤ 14.2 mg/LFeb
Nitrogen, ammonia total [as N]daily maximum≤ 16.2 mg/LAug
Nitrogen, ammonia total [as N]daily maximum≤ 15.7 mg/LOct
Nitrogen, ammonia total [as N]daily maximum≤ 15.2 mg/LJan
Nitrogen, ammonia total [as N]daily maximum≤ 14.7 mg/LMar
Nitrogen, ammonia total [as N]daily maximum≤ 15.2 mg/LJul
Nitrogen, ammonia total [as N]daily maximum≤ 14.7 mg/LNov
Nitrogen, ammonia total [as N]daily maximum≤ 14.4 mg/LJun
Nitrogen, ammonia total [as N]30-day average≤ 20.8 lb/dMay
Nitrogen, ammonia total [as N]30-day average≤ 12.7 lb/dSep
Nitrogen, ammonia total [as N]30-day average≤ 29.6 lb/dDec
Nitrogen, ammonia total [as N]30-day average≤ 18.3 lb/dApr
Nitrogen, ammonia total [as N]30-day average≤ 47.3 lb/dFeb
Nitrogen, ammonia total [as N]30-day average≤ 11.4 lb/dAug
Nitrogen, ammonia total [as N]30-day average≤ 18.6 lb/dOct
Nitrogen, ammonia total [as N]30-day average≤ 40.8 lb/dJan
Nitrogen, ammonia total [as N]30-day average≤ 40.8 lb/dMar
Nitrogen, ammonia total [as N]30-day average≤ 12 lb/dJul
Nitrogen, ammonia total [as N]30-day average≤ 27.8 lb/dNov
Nitrogen, ammonia total [as N]30-day average≤ 15.7 lb/dJun
Nitrogen, ammonia total [as N]daily maximum≤ 181.9 lb/dMay
Nitrogen, ammonia total [as N]daily maximum≤ 197.5 lb/dSep
Nitrogen, ammonia total [as N]daily maximum≤ 191.2 lb/dDec
Nitrogen, ammonia total [as N]daily maximum≤ 188 lb/dApr
Nitrogen, ammonia total [as N]daily maximum≤ 170 lb/dFeb
Nitrogen, ammonia total [as N]daily maximum≤ 171.3 lb/dAug
Nitrogen, ammonia total [as N]daily maximum≤ 188 lb/dOct
Nitrogen, ammonia total [as N]daily maximum≤ 181.9 lb/dJan
Nitrogen, ammonia total [as N]daily maximum≤ 175.9 lb/dMar
Nitrogen, ammonia total [as N]daily maximum≤ 171.3 lb/dJul
Nitrogen, ammonia total [as N]daily maximum≤ 175.9 lb/dNov
Nitrogen, ammonia total [as N]daily maximum≤ 172.9 lb/dJun
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
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≤ 4655 lb/dall year
Chloride [as Cl]daily maximum≤ 7531 lb/dall 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≤ .202 lb/dall year
Copper, total [as Cu]daily maximum≤ .3221 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≤ 299 lb/dall year
BOD, carbonaceous [5 day, 20 C]7-day average≤ 479 lb/dall year

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

· Save this facility as a site · Superfund sites nearby · Your permits on one board

On EPA ECHO: Facility report · DMR history

Your permit document is the final word. As JSON: /api/v1/permits/IA0023710 · MCP: https://passage-data.com/mcp