Rock Cut State Park — NPDES permit IL0054054: limits, due date and EPA's record

Land, Mineral, Wildlife Conservation, Loves Park, Illinois. NPDES permit IL0054054, in force until Feb 28, 2029. Last 12 months: over a limit 5 times (last October 2025). Source: EPA ECHO, Oct 22, 2026.

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

Period ending	Parameter	Reported	Limit	Over by
October 2025	BOD, carbonaceous [5 day, 20 C], monthly average	11.3 mg/L	≤ 10 mg/L	13%
October 2025	Nitrogen, ammonia total [as N], daily maximum	10 mg/L	≤ 4.7 mg/L	113%
October 2025	Nitrogen, ammonia total [as N], monthly average	.25 lb/d	≤ .13 lb/d	92%
October 2025	Nitrogen, ammonia total [as N], monthly average	10 mg/L	≤ 1.3 mg/L	669%
October 2025	Nitrogen, ammonia total [as N], weekly average	10 mg/L	≤ 3.3 mg/L	203%

Limits in force (39)

Parameter	Statistic	Limit	Months	Outfall
Oxygen, dissolved [DO]	monthly average minimum	≥ 5.5 mg/L	Jan, Feb, Aug, Sep, Oct, Nov, Dec	002
Oxygen, dissolved [DO]	minimum weekly average	≥ 4 mg/L	Jan, Feb, Aug, Sep, Oct, Nov, Dec	002
Oxygen, dissolved [DO]	minimum weekly average	≥ 6 mg/L	Mar–Jul	002
Oxygen, dissolved [DO]	daily minimum	≥ 3.5 mg/L	Jan, Feb, Aug, Sep, Oct, Nov, Dec	002
Oxygen, dissolved [DO]	daily minimum	≥ 5 mg/L	Mar–Jul	002
pH	minimum	≥ 6 SU	all year	002
pH	maximum	≤ 9 SU	all year	002
Solids, total suspended	monthly average	≤ 12 mg/L	all year	002
Solids, total suspended	daily maximum	≤ 24 mg/L	all year	002
Solids, total suspended	monthly average	≤ 1.2 lb/d	all year	002
Solids, total suspended	daily maximum	≤ 2.3 lb/d	all year	002
Nitrogen, ammonia total [as N]	monthly average	≤ 1.3 mg/L	Mar, Apr, May, Sep, Oct	002
Nitrogen, ammonia total [as N]	monthly average	≤ 1 mg/L	Jun–Aug	002
Nitrogen, ammonia total [as N]	monthly average	≤ 2.9 mg/L	Jan, Feb, Nov, Dec	002
Nitrogen, ammonia total [as N]	daily maximum	≤ 4.7 mg/L	Mar, Apr, May, Sep, Oct	002
Nitrogen, ammonia total [as N]	daily maximum	≤ 4.7 mg/L	Jun–Aug	002
Nitrogen, ammonia total [as N]	daily maximum	≤ 4.7 mg/L	Jan, Feb, Nov, Dec	002
Nitrogen, ammonia total [as N]	monthly average	≤ .13 lb/d	Mar, Apr, May, Sep, Oct	002
Nitrogen, ammonia total [as N]	monthly average	≤ .1 lb/d	Jun–Aug	002
Nitrogen, ammonia total [as N]	monthly average	≤ .28 lb/d	Jan, Feb, Nov, Dec	002
Nitrogen, ammonia total [as N]	daily maximum	≤ .46 lb/d	Mar, Apr, May, Sep, Oct	002
Nitrogen, ammonia total [as N]	daily maximum	≤ .46 lb/d	Jun–Aug	002
Nitrogen, ammonia total [as N]	daily maximum	≤ .46 lb/d	Jan, Feb, Nov, Dec	002
Nitrogen, ammonia total [as N]	weekly average	≤ 2.5 mg/L	Jun–Aug	002
Nitrogen, ammonia total [as N]	weekly average	≤ 3.3 mg/L	Mar, Apr, May, Sep, Oct	002
Nitrogen, ammonia total [as N]	weekly average	≤ .24 lb/d	Jun–Aug	002
Nitrogen, ammonia total [as N]	weekly average	≤ .32 lb/d	Mar, Apr, May, Sep, Oct	002
Flow, in conduit or thru treatment plant	monthly average	report only (MGD)	all year	002
Flow, in conduit or thru treatment plant	daily maximum	report only (MGD)	all year	002
Chlorine, total residual	daily maximum	≤ .05 mg/L	all year	002
Coliform, fecal general	daily maximum	≤ 400 #/100mL	all year	002
BOD, carbonaceous [5 day, 20 C]	monthly average	≤ 10 mg/L	all year	002
BOD, carbonaceous [5 day, 20 C]	daily maximum	≤ 20 mg/L	all year	002
BOD, carbonaceous [5 day, 20 C]	monthly average	≤ 1 lb/d	all year	002
BOD, carbonaceous [5 day, 20 C]	daily maximum	≤ 2 lb/d	all year	002
BOD, 5-day, 20 deg. C	monthly average	report only (mg/L)	all year	INF
Solids, total suspended	monthly average	report only (mg/L)	all year	INF
Flow, in conduit or thru treatment plant	monthly average	report only (MGD)	all year	INF
Flow, in conduit or thru treatment plant	daily maximum	report only (MGD)	all year	INF

How strict are these limits?

Your permit document is the final word. As JSON: /api/v1/permits/IL0054054 · MCP: https://passage-data.com/mcp