NORRIS CITY STP, VILLAGE OF
NPDES ID: IL0030155
E — SNC: Effluent violation (monthly average limit)
The facility discharged more of a pollutant than its permit allows, based on a monthly average.
This quarter: 12 effluent violations, 1 single-event violation.
Violations
May 31, 2026
Solids, total suspended
283% over limit
Discharged 92 mg/L against a permitted limit of 24 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Oxygen, dissolved [DO]
82% over limit
Discharged 0.9 mg/L against a permitted limit of 5 mg/L (DAILY MN)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
160% over limit
Discharged 13.8 mg/L against a permitted limit of 5.3 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Oxygen, dissolved [DO]
27% over limit
Discharged 4.4 mg/L against a permitted limit of 6 mg/L (MN WK AV)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
135% over limit
Discharged 47 mg/L against a permitted limit of 20 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
120% over limit
Discharged 22 mg/L against a permitted limit of 10 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
175% over limit
Discharged 4.4 mg/L against a permitted limit of 1.6 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
225% over limit
Discharged 39 mg/L against a permitted limit of 12 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Chlorine, total residual
20% over limit
Discharged 0.06 mg/L against a permitted limit of 0.05 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
April 30, 2026
Oxygen, dissolved [DO]
16% over limit
Discharged 5.05 mg/L against a permitted limit of 6 mg/L (MN WK AV)
DMR, Limited - Numeric Violation
Oxygen, dissolved [DO]
32% over limit
Discharged 3.4 mg/L against a permitted limit of 5 mg/L (DAILY MN)
DMR, Limited - Numeric Violation
March 31, 2026
Oxygen, dissolved [DO]
16% over limit
Discharged 4.2 mg/L against a permitted limit of 5 mg/L (DAILY MN)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
31% over limit
Discharged 4.99399996 kg/d against a permitted limit of 3.81359997 kg/d (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
334% over limit
Discharged 8.25 mg/L against a permitted limit of 1.9 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
185% over limit
Discharged 22.8 mg/L against a permitted limit of 8 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
72% over limit
Discharged 8.25 mg/L against a permitted limit of 4.8 mg/L (WKLY AVG)
DMR, Limited - Numeric Violation
February 28, 2026
Oxygen, dissolved [DO]
4% over limit
Discharged 5.3 mg/L against a permitted limit of 5.5 mg/L (MO AV MN)
DMR, Limited - Numeric Violation
January 31, 2026
Oxygen, dissolved [DO]
19% over limit
Discharged 4.46 mg/L against a permitted limit of 5.5 mg/L (MO AV MN)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
95% over limit
Discharged 7.6 mg/L against a permitted limit of 3.9 mg/L (MO AVG)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
95% over limit
Discharged 39 mg/L against a permitted limit of 20 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Oxygen, dissolved [DO]
43% over limit
Discharged 2 mg/L against a permitted limit of 3.5 mg/L (DAILY MN)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
178% over limit
Discharged 20 mg/L against a permitted limit of 7.2 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
64% over limit
Discharged 16.4 mg/L against a permitted limit of 10 mg/L (MO AVG)
DMR, Limited - Numeric Violation
December 31, 2025
BOD, carbonaceous [5 day, 20 C]
6% over limit
Discharged 10.6 mg/L against a permitted limit of 10 mg/L (MO AVG)
DMR, Limited - Numeric Violation
November 30, 2025
Nitrogen, ammonia total [as N]
40% over limit
Discharged 10.1 mg/L against a permitted limit of 7.2 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
October 31, 2025
Nitrogen, ammonia total [as N]
31% over limit
Discharged 2.1 mg/L against a permitted limit of 1.6 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
49% over limit
Discharged 7.9 mg/L against a permitted limit of 5.3 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
July 31, 2025
Nitrogen, ammonia total [as N]
27% over limit
Discharged 1.27 mg/L against a permitted limit of 1 mg/L (MO AVG)
DMR, Limited - Numeric Violation
June 30, 2025
Oxygen, dissolved [DO]
2% over limit
Discharged 5.89 mg/L against a permitted limit of 6 mg/L (MN WK AV)
DMR, Limited - Numeric Violation
April 30, 2025
BOD, carbonaceous [5 day, 20 C]
0% over limit
Discharged 9 mg/L against a permitted limit of 20 mg/L (DAILY MX)
DMR, Limited - Overdue
Nitrogen, ammonia total [as N]
0% over limit
Discharged 0.13 mg/L against a permitted limit of 5.3 mg/L (DAILY MX)
DMR, Limited - Overdue
Flow, in conduit or thru treatment plant
0% over limit
Discharged 0.466 MGD against a permitted limit of 0 MGD (DAILY MX)
DMR, Monitor Only - Overdue
Oxygen, dissolved [DO]
0% over limit
Discharged 6.3 mg/L against a permitted limit of 5 mg/L (DAILY MN)
DMR, Limited - Overdue
Solids, total suspended
0% over limit
Discharged 4.25 mg/L against a permitted limit of 12 mg/L (MO AVG)
DMR, Limited - Overdue
Nitrogen, ammonia total [as N]
0% over limit
Discharged 0.13166 kg/d against a permitted limit of 9.53399992 kg/d (WKLY AVG)
DMR, Limited - Overdue
Flow, in conduit or thru treatment plant
0% over limit
Discharged 0.466 MGD against a permitted limit of 0 MGD (DAILY MX)
DMR, Monitor Only - Overdue
Nitrogen, ammonia total [as N]
0% over limit
Discharged 0.075 mg/L against a permitted limit of 1.6 mg/L (MO AVG)
DMR, Limited - Overdue
Nitrogen, ammonia total [as N]
0% over limit
Discharged 0.08172 kg/d against a permitted limit of 3.22339997 kg/d (MO AVG)
DMR, Limited - Overdue
Oxygen, dissolved [DO]
0% over limit
Discharged 6.37 mg/L against a permitted limit of 6 mg/L (MN WK AV)
DMR, Limited - Overdue
Flow, in conduit or thru treatment plant
0% over limit
Discharged 0.29 MGD against a permitted limit of 0 MGD (MO AVG)
DMR, Monitor Only - Overdue
pH
0% over limit
Discharged 7 SU against a permitted limit of 6 SU (MINIMUM)
DMR, Limited - Overdue
Solids, total suspended
0% over limit
Discharged 68 mg/L against a permitted limit of 0 mg/L (MO AVG)
DMR, Monitor Only - Overdue
Flow, in conduit or thru treatment plant
0% over limit
Discharged 0.24 MGD against a permitted limit of 0 MGD (MO AVG)
DMR, Monitor Only - Overdue
BOD, carbonaceous [5 day, 20 C]
0% over limit
Discharged 15.88999987 kg/d against a permitted limit of 39.95199966 kg/d (DAILY MX)
DMR, Limited - Overdue
BOD, carbonaceous [5 day, 20 C]
0% over limit
Discharged 5.5 mg/L against a permitted limit of 10 mg/L (MO AVG)
DMR, Limited - Overdue
Nitrogen, ammonia total [as N]
0% over limit
Discharged 0.227 kg/d against a permitted limit of 10.44199991 kg/d (DAILY MX)
DMR, Limited - Overdue
Solids, total suspended
0% over limit
Discharged 8 mg/L against a permitted limit of 24 mg/L (DAILY MX)
DMR, Limited - Overdue
BOD, 5-day, 20 deg. C
0% over limit
Discharged 74.25 mg/L against a permitted limit of 0 mg/L (MO AVG)
DMR, Monitor Only - Overdue
Nitrogen, ammonia total [as N]
0% over limit
Discharged 0.075 mg/L against a permitted limit of 4.8 mg/L (WKLY AVG)
DMR, Limited - Overdue
Solids, total suspended
0% over limit
Discharged 14.07399988 kg/d against a permitted limit of 48.1239996 kg/d (DAILY MX)
DMR, Limited - Overdue
Solids, total suspended
0% over limit
Discharged 3.85899997 kg/d against a permitted limit of 24.0619998 kg/d (MO AVG)
DMR, Limited - Overdue
pH
0% over limit
Discharged 7.5 SU against a permitted limit of 9 SU (MAXIMUM)
DMR, Limited - Overdue
BOD, carbonaceous [5 day, 20 C]
0% over limit
Discharged 4.99399996 kg/d against a permitted limit of 19.97599983 kg/d (MO AVG)
DMR, Limited - Overdue
Chlorine, total residual
0% over limit
Discharged 0 mg/L against a permitted limit of 0.05 mg/L (DAILY MX)
DMR, Limited - Overdue
First flagged
April 14, 2026 (3 months ago)
Last confirmed
August 1, 2026 (4 days ago)