City of Charles City — NPDES permit IA0022039: limits, due date and EPA's record

Sewage treatment plant, major discharger, Charles City, Iowa. NPDES permit IA0022039 expired May 31, 2026; its limits still apply. Last 12 months: no values over a limit. Source: EPA ECHO, Oct 22, 2026.

Limits in force (209)

Parameter	Statistic	Limit	Months	Outfall
Streamflow	30-day average	report only (cfs)	all year	001
Streamflow	daily maximum	report only (cfs)	all year	001
BOD, 5-day, 20 deg. C	30-day average	report only (mg/L)	all year	001
BOD, 5-day, 20 deg. C	daily maximum	report only (mg/L)	all year	001
BOD, 5-day, 20 deg. C	30-day average	report only (lb/d)	all year	001
BOD, 5-day, 20 deg. C	daily maximum	report only (lb/d)	all year	001
pH	daily minimum	≥ 6 SU	all year	001
pH	daily maximum	≤ 9 SU	all year	001
pH	30-day average	report only (SU)	all year	001
pH	daily maximum	report only (SU)	all year	001
Solids, total suspended	30-day average	≤ 30 mg/L	all year	001
Solids, total suspended	7-day average	≤ 45 mg/L	all year	001
Solids, total suspended	30-day average	≤ 1166 lb/d	all year	001
Solids, total suspended	7-day average	≤ 1749 lb/d	all year	001
Solids, total suspended	30-day average	report only (mg/L)	all year	001
Solids, total suspended	daily maximum	report only (mg/L)	all year	001
Solids, total suspended	30-day average	report only (lb/d)	all year	001
Solids, total suspended	daily maximum	report only (lb/d)	all year	001
Nitrogen, total [as N]	30-day average	≤ 370.5 lb/d	all year	001
Nitrogen, total [as N]	daily maximum	≤ 606.5 lb/d	all year	001
Nitrogen, total [as N]	30-day average	report only (mg/L)	all year	001
Nitrogen, total [as N]	daily maximum	report only (mg/L)	all year	001
Nitrogen, total [as N]	30-day average	report only (lb/d)	all year	001
Nitrogen, total [as N]	daily maximum	report only (lb/d)	all year	001
Nitrogen, ammonia total [as N]	30-day average	≤ 22.2 mg/L	Jun	001
Nitrogen, ammonia total [as N]	30-day average	≤ 27.4 mg/L	Oct	001
Nitrogen, ammonia total [as N]	30-day average	≤ 29.4 mg/L	May	001
Nitrogen, ammonia total [as N]	30-day average	≤ 57.5 mg/L	Jan	001
Nitrogen, ammonia total [as N]	30-day average	≤ 19 mg/L	Sep	001
Nitrogen, ammonia total [as N]	30-day average	≤ 44.9 mg/L	Dec	001
Nitrogen, ammonia total [as N]	30-day average	≤ 27.4 mg/L	Apr	001
Nitrogen, ammonia total [as N]	30-day average	≤ 40 mg/L	Nov	001
Nitrogen, ammonia total [as N]	30-day average	≤ 33.7 mg/L	Mar	001
Nitrogen, ammonia total [as N]	30-day average	≤ 63.9 mg/L	Feb	001
Nitrogen, ammonia total [as N]	30-day average	≤ 16.6 mg/L	Aug	001
Nitrogen, ammonia total [as N]	30-day average	≤ 17.7 mg/L	Jul	001
Nitrogen, ammonia total [as N]	daily maximum	≤ 79.4 mg/L	Jun	001
Nitrogen, ammonia total [as N]	daily maximum	≤ 70.4 mg/L	Oct	001
Nitrogen, ammonia total [as N]	daily maximum	≤ 80.4 mg/L	May	001
Nitrogen, ammonia total [as N]	daily maximum	≤ 93.6 mg/L	Jan	001
Nitrogen, ammonia total [as N]	daily maximum	≤ 71.7 mg/L	Sep	001
Nitrogen, ammonia total [as N]	daily maximum	≤ 70.7 mg/L	Dec	001
Nitrogen, ammonia total [as N]	daily maximum	≤ 70.3 mg/L	Apr	001
Nitrogen, ammonia total [as N]	daily maximum	≤ 68.9 mg/L	Nov	001
Nitrogen, ammonia total [as N]	daily maximum	≤ 91.8 mg/L	Mar	001
Nitrogen, ammonia total [as N]	daily maximum	≤ 107.5 mg/L	Feb	001
Nitrogen, ammonia total [as N]	daily maximum	≤ 82 mg/L	Aug	001
Nitrogen, ammonia total [as N]	daily maximum	≤ 84.1 mg/L	Jul	001
Nitrogen, ammonia total [as N]	30-day average	≤ 461.9 lb/d	Jun	001
Nitrogen, ammonia total [as N]	30-day average	≤ 576.3 lb/d	Oct	001
Nitrogen, ammonia total [as N]	30-day average	≤ 613.6 lb/d	May	001
Nitrogen, ammonia total [as N]	30-day average	≤ 1196.3 lb/d	Jan	001
Nitrogen, ammonia total [as N]	30-day average	≤ 402 lb/d	Sep	001
Nitrogen, ammonia total [as N]	30-day average	≤ 950.5 lb/d	Dec	001
Nitrogen, ammonia total [as N]	30-day average	≤ 579.3 lb/d	Apr	001
Nitrogen, ammonia total [as N]	30-day average	≤ 834.2 lb/d	Nov	001
Nitrogen, ammonia total [as N]	30-day average	≤ 700.5 lb/d	Mar	001
Nitrogen, ammonia total [as N]	30-day average	≤ 1319.9 lb/d	Feb	001
Nitrogen, ammonia total [as N]	30-day average	≤ 348.4 lb/d	Aug	001
Nitrogen, ammonia total [as N]	30-day average	≤ 373.5 lb/d	Jul	001
Nitrogen, ammonia total [as N]	daily maximum	≤ 1687.9 lb/d	Jun	001
Nitrogen, ammonia total [as N]	daily maximum	≤ 1518.9 lb/d	Oct	001
Nitrogen, ammonia total [as N]	daily maximum	≤ 1712.7 lb/d	May	001
Nitrogen, ammonia total [as N]	daily maximum	≤ 1976.6 lb/d	Jan	001
Nitrogen, ammonia total [as N]	daily maximum	≤ 1550 lb/d	Sep	001
Nitrogen, ammonia total [as N]	daily maximum	≤ 1526.8 lb/d	Dec	001
Nitrogen, ammonia total [as N]	daily maximum	≤ 1516.6 lb/d	Apr	001
Nitrogen, ammonia total [as N]	daily maximum	≤ 1480.3 lb/d	Nov	001
Nitrogen, ammonia total [as N]	daily maximum	≤ 1936.8 lb/d	Mar	001
Nitrogen, ammonia total [as N]	daily maximum	≤ 2245.3 lb/d	Feb	001
Nitrogen, ammonia total [as N]	daily maximum	≤ 1753.8 lb/d	Aug	001
Nitrogen, ammonia total [as N]	daily maximum	≤ 1807.4 lb/d	Jul	001
Nitrogen, Kjeldahl, total [as N]	30-day average	report only (mg/L)	all year	001
Nitrogen, Kjeldahl, total [as N]	daily maximum	report only (mg/L)	all year	001
Nitrogen, Kjeldahl, total [as N]	30-day average	report only (lb/d)	all year	001
Nitrogen, Kjeldahl, total [as N]	daily maximum	report only (lb/d)	all year	001
Phosphorus, total [as P]	30-day average	report only (mg/L)	all year	001
Phosphorus, total [as P]	daily maximum	report only (mg/L)	all year	001
Phosphorus, total [as P]	30-day average	report only (lb/d)	all year	001
Phosphorus, total [as P]	daily maximum	report only (lb/d)	all year	001
E. coli	geometric mean	≤ 126 #/100mL	Mar–Nov	001
Toxicity [acute], Ceriodaphnia dubia	daily maximum	≤ 1 N=0;Y=1	all year	001
Toxicity [acute], Pimephales promelas [Fathead Minnow]	daily maximum	≤ 1 N=0;Y=1	all year	001
BOD, carbonaceous [5 day, 20 C]	30-day average	≤ 25 mg/L	all year	001
BOD, carbonaceous [5 day, 20 C]	7-day average	≤ 40 mg/L	all year	001
BOD, carbonaceous [5 day, 20 C]	30-day average	≤ 972 lb/d	all year	001
BOD, carbonaceous [5 day, 20 C]	7-day average	≤ 1555 lb/d	all year	001
pH	daily minimum	≥ 6 SU	all year	003
pH	daily maximum	≤ 9 SU	all year	003
Solids, total suspended	30-day average	≤ 30 mg/L	all year	003
Solids, total suspended	7-day average	≤ 45 mg/L	all year	003
Solids, total suspended	30-day average	≤ 1166 lb/d	all year	003
Solids, total suspended	7-day average	≤ 1749 lb/d	all year	003
Nitrogen, total [as N]	30-day average	≤ 370.5 lb/d	all year	003
Nitrogen, total [as N]	daily maximum	≤ 606.5 lb/d	all year	003
Nitrogen, ammonia total [as N]	30-day average	≤ 24.5 mg/L	Nov	003
Nitrogen, ammonia total [as N]	30-day average	≤ 25.8 mg/L	Apr	003
Nitrogen, ammonia total [as N]	30-day average	≤ 18.8 mg/L	Jul	003
Nitrogen, ammonia total [as N]	30-day average	≤ 26.2 mg/L	Dec	003
Nitrogen, ammonia total [as N]	30-day average	≤ 17.8 mg/L	Aug	003
Nitrogen, ammonia total [as N]	30-day average	≤ 29.7 mg/L	Feb	003
Nitrogen, ammonia total [as N]	30-day average	≤ 26.7 mg/L	May	003
Nitrogen, ammonia total [as N]	30-day average	≤ 19.7 mg/L	Sep	003
Nitrogen, ammonia total [as N]	30-day average	≤ 27.8 mg/L	Mar	003
Nitrogen, ammonia total [as N]	30-day average	≤ 28.6 mg/L	Jan	003
Nitrogen, ammonia total [as N]	30-day average	≤ 25.8 mg/L	Oct	003
Nitrogen, ammonia total [as N]	30-day average	≤ 24.6 mg/L	Jun	003
Nitrogen, ammonia total [as N]	daily maximum	≤ 24.5 mg/L	Nov	003
Nitrogen, ammonia total [as N]	daily maximum	≤ 25.8 mg/L	Apr	003
Nitrogen, ammonia total [as N]	daily maximum	≤ 29.9 mg/L	Jul	003
Nitrogen, ammonia total [as N]	daily maximum	≤ 26.2 mg/L	Dec	003
Nitrogen, ammonia total [as N]	daily maximum	≤ 28.1 mg/L	Aug	003
Nitrogen, ammonia total [as N]	daily maximum	≤ 29.7 mg/L	Feb	003
Nitrogen, ammonia total [as N]	daily maximum	≤ 26.7 mg/L	May	003
Nitrogen, ammonia total [as N]	daily maximum	≤ 26.9 mg/L	Sep	003
Nitrogen, ammonia total [as N]	daily maximum	≤ 27.8 mg/L	Mar	003
Nitrogen, ammonia total [as N]	daily maximum	≤ 28.6 mg/L	Jan	003
Nitrogen, ammonia total [as N]	daily maximum	≤ 25.8 mg/L	Oct	003
Nitrogen, ammonia total [as N]	daily maximum	≤ 25.8 mg/L	Jun	003
Nitrogen, ammonia total [as N]	30-day average	≤ 952.4 lb/d	Nov	003
Nitrogen, ammonia total [as N]	30-day average	≤ 1003.3 lb/d	Apr	003
Nitrogen, ammonia total [as N]	30-day average	≤ 729.3 lb/d	Jul	003
Nitrogen, ammonia total [as N]	30-day average	≤ 1016.8 lb/d	Dec	003
Nitrogen, ammonia total [as N]	30-day average	≤ 692 lb/d	Aug	003
Nitrogen, ammonia total [as N]	30-day average	≤ 1153.5 lb/d	Feb	003
Nitrogen, ammonia total [as N]	30-day average	≤ 1037.6 lb/d	May	003
Nitrogen, ammonia total [as N]	30-day average	≤ 767.5 lb/d	Sep	003
Nitrogen, ammonia total [as N]	30-day average	≤ 1081.6 lb/d	Mar	003
Nitrogen, ammonia total [as N]	30-day average	≤ 1112.6 lb/d	Jan	003
Nitrogen, ammonia total [as N]	30-day average	≤ 1004 lb/d	Oct	003
Nitrogen, ammonia total [as N]	30-day average	≤ 954.3 lb/d	Jun	003
Nitrogen, ammonia total [as N]	daily maximum	≤ 952.4 lb/d	Nov	003
Nitrogen, ammonia total [as N]	daily maximum	≤ 1003.3 lb/d	Apr	003
Nitrogen, ammonia total [as N]	daily maximum	≤ 1161.4 lb/d	Jul	003
Nitrogen, ammonia total [as N]	daily maximum	≤ 1016.8 lb/d	Dec	003
Nitrogen, ammonia total [as N]	daily maximum	≤ 1090.6 lb/d	Aug	003
Nitrogen, ammonia total [as N]	daily maximum	≤ 1153.5 lb/d	Feb	003
Nitrogen, ammonia total [as N]	daily maximum	≤ 1037.6 lb/d	May	003
Nitrogen, ammonia total [as N]	daily maximum	≤ 1045.2 lb/d	Sep	003
Nitrogen, ammonia total [as N]	daily maximum	≤ 1081.6 lb/d	Mar	003
Nitrogen, ammonia total [as N]	daily maximum	≤ 1112.6 lb/d	Jan	003
Nitrogen, ammonia total [as N]	daily maximum	≤ 1004 lb/d	Oct	003
Nitrogen, ammonia total [as N]	daily maximum	≤ 1001.5 lb/d	Jun	003
E. coli	geometric mean	≤ 126 #/100mL	Mar–Nov	003
BOD, carbonaceous [5 day, 20 C]	30-day average	≤ 25 mg/L	all year	003
BOD, carbonaceous [5 day, 20 C]	7-day average	≤ 40 mg/L	all year	003
BOD, carbonaceous [5 day, 20 C]	30-day average	≤ 972 lb/d	all year	003
BOD, carbonaceous [5 day, 20 C]	7-day average	≤ 1555 lb/d	all year	003
pH	daily minimum	≥ 6 SU	all year	004
pH	daily maximum	≤ 9 SU	all year	004
Solids, total suspended	30-day average	≤ 30 mg/L	all year	004
Solids, total suspended	7-day average	≤ 45 mg/L	all year	004
Solids, total suspended	30-day average	≤ 1166 lb/d	all year	004
Solids, total suspended	7-day average	≤ 1749 lb/d	all year	004
Nitrogen, total [as N]	30-day average	≤ 370.5 lb/d	all year	004
Nitrogen, total [as N]	daily maximum	≤ 606.5 lb/d	all year	004
Nitrogen, ammonia total [as N]	30-day average	≤ 19.5 mg/L	Dec	004
Nitrogen, ammonia total [as N]	30-day average	≤ 8.3 mg/L	Jul	004
Nitrogen, ammonia total [as N]	30-day average	≤ 8.8 mg/L	Sep	004
Nitrogen, ammonia total [as N]	30-day average	≤ 10.9 mg/L	Jun	004
Nitrogen, ammonia total [as N]	30-day average	≤ 18 mg/L	Nov	004
Nitrogen, ammonia total [as N]	30-day average	≤ 19.1 mg/L	Feb	004
Nitrogen, ammonia total [as N]	30-day average	≤ 19.5 mg/L	Jan	004
Nitrogen, ammonia total [as N]	30-day average	≤ 12.6 mg/L	Apr	004
Nitrogen, ammonia total [as N]	30-day average	≤ 7.9 mg/L	Aug	004
Nitrogen, ammonia total [as N]	30-day average	≤ 16.8 mg/L	Mar	004
Nitrogen, ammonia total [as N]	30-day average	≤ 14.5 mg/L	May	004
Nitrogen, ammonia total [as N]	30-day average	≤ 13 mg/L	Oct	004
Nitrogen, ammonia total [as N]	daily maximum	≤ 19.5 mg/L	Dec	004
Nitrogen, ammonia total [as N]	daily maximum	≤ 21.8 mg/L	Jul	004
Nitrogen, ammonia total [as N]	daily maximum	≤ 20.1 mg/L	Sep	004
Nitrogen, ammonia total [as N]	daily maximum	≤ 18.2 mg/L	Jun	004
Nitrogen, ammonia total [as N]	daily maximum	≤ 18 mg/L	Nov	004
Nitrogen, ammonia total [as N]	daily maximum	≤ 19.1 mg/L	Feb	004
Nitrogen, ammonia total [as N]	daily maximum	≤ 19.5 mg/L	Jan	004
Nitrogen, ammonia total [as N]	daily maximum	≤ 19.2 mg/L	Apr	004
Nitrogen, ammonia total [as N]	daily maximum	≤ 20.2 mg/L	Aug	004
Nitrogen, ammonia total [as N]	daily maximum	≤ 18.9 mg/L	Mar	004
Nitrogen, ammonia total [as N]	daily maximum	≤ 19 mg/L	May	004
Nitrogen, ammonia total [as N]	daily maximum	≤ 19.2 mg/L	Oct	004
Nitrogen, ammonia total [as N]	30-day average	≤ 461.9 lb/d	Dec	004
Nitrogen, ammonia total [as N]	30-day average	≤ 186.4 lb/d	Jul	004
Nitrogen, ammonia total [as N]	30-day average	≤ 196.1 lb/d	Sep	004
Nitrogen, ammonia total [as N]	30-day average	≤ 243.7 lb/d	Jun	004
Nitrogen, ammonia total [as N]	30-day average	≤ 434.3 lb/d	Nov	004
Nitrogen, ammonia total [as N]	30-day average	≤ 650.8 lb/d	Feb	004
Nitrogen, ammonia total [as N]	30-day average	≤ 638.8 lb/d	Jan	004
Nitrogen, ammonia total [as N]	30-day average	≤ 282.7 lb/d	Apr	004
Nitrogen, ammonia total [as N]	30-day average	≤ 176.9 lb/d	Aug	004
Nitrogen, ammonia total [as N]	30-day average	≤ 377.3 lb/d	Mar	004
Nitrogen, ammonia total [as N]	30-day average	≤ 323.1 lb/d	May	004
Nitrogen, ammonia total [as N]	30-day average	≤ 290.2 lb/d	Oct	004
Nitrogen, ammonia total [as N]	daily maximum	≤ 694.1 lb/d	Dec	004
Nitrogen, ammonia total [as N]	daily maximum	≤ 771.5 lb/d	Jul	004
Nitrogen, ammonia total [as N]	daily maximum	≤ 717 lb/d	Sep	004
Nitrogen, ammonia total [as N]	daily maximum	≤ 638 lb/d	Jun	004
Nitrogen, ammonia total [as N]	daily maximum	≤ 640 lb/d	Nov	004
Nitrogen, ammonia total [as N]	daily maximum	≤ 650.8 lb/d	Feb	004
Nitrogen, ammonia total [as N]	daily maximum	≤ 679.6 lb/d	Jan	004
Nitrogen, ammonia total [as N]	daily maximum	≤ 683 lb/d	Apr	004
Nitrogen, ammonia total [as N]	daily maximum	≤ 713.4 lb/d	Aug	004
Nitrogen, ammonia total [as N]	daily maximum	≤ 657.6 lb/d	Mar	004
Nitrogen, ammonia total [as N]	daily maximum	≤ 669.3 lb/d	May	004
Nitrogen, ammonia total [as N]	daily maximum	≤ 683.1 lb/d	Oct	004
E. coli	geometric mean	≤ 126 #/100mL	Mar–Nov	004
BOD, carbonaceous [5 day, 20 C]	30-day average	≤ 25 mg/L	all year	004
BOD, carbonaceous [5 day, 20 C]	7-day average	≤ 40 mg/L	all year	004
BOD, carbonaceous [5 day, 20 C]	30-day average	≤ 972 lb/d	all year	004
BOD, carbonaceous [5 day, 20 C]	7-day average	≤ 1555 lb/d	all year	004

How strict are these limits?

Your permit document is the final word. As JSON: /api/v1/permits/IA0022039 · MCP: https://passage-data.com/mcp