MAINESBURG STP/COLLECTION SYSTEM
NPDES ID: PA0209511
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: 2 effluent violations, 2 single-event violations, 25 reporting violations.
Violations
May 31, 2026
Coliform, fecal general
Limit violation
Discharged 2419.6 MPN/100mL against a permitted limit of 1000 MPN/100mL (INST MAX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
23% over limit
Discharged 6.4 mg/L against a permitted limit of 5.2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
March 31, 2026
Coliform, fecal general
0% over limit
Discharged 0 MPN/100mL against a permitted limit of 2000 MPN/100mL (GEO MEAN)
DMR, Limited - Overdue
Chlorine, total residual
0% over limit
Discharged 0 mg/L against a permitted limit of 0.89 mg/L (INST MAX)
DMR, Limited - Overdue
Oxygen, dissolved [DO]
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (DAILY MN)
DMR, Monitor Only - Overdue
Solids, total suspended
0% over limit
Discharged 0 mg/L against a permitted limit of 30 mg/L (MO AVG)
DMR, Limited - Overdue
Flow, in conduit or thru treatment plant
0% over limit
Discharged 0 MGD against a permitted limit of 0 MGD (MO AVG)
DMR, Monitor Only - Overdue
Solids, total suspended
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (MO AVG)
DMR, Monitor Only - Overdue
BOD, 5-day, 20 deg. C
0% over limit
Discharged 0 kg/d against a permitted limit of 0 kg/d (MO AVG)
DMR, Monitor Only - Overdue
BOD, 5-day, 20 deg. C
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (MO AVG)
DMR, Monitor Only - Overdue
Solids, total suspended
0% over limit
Discharged 0 kg/d against a permitted limit of 0 kg/d (MO AVG)
DMR, Monitor Only - Overdue
Solids, total suspended
0% over limit
Discharged 0 mg/L against a permitted limit of 45 mg/L (WKLY AVG)
DMR, Limited - Overdue
Flow, in conduit or thru treatment plant
0% over limit
Discharged 0 MGD against a permitted limit of 0 MGD (DAILY MX)
DMR, Monitor Only - Overdue
pH
0% over limit
Discharged 0 SU against a permitted limit of 6 SU (INST MIN)
DMR, Limited - Overdue
BOD, 5-day, 20 deg. C
0% over limit
Discharged 0 kg/d against a permitted limit of 0 kg/d (DAILY MX)
DMR, Monitor Only - Overdue
Solids, total suspended
0% over limit
Discharged 0 kg/d against a permitted limit of 1.72519999 kg/d (MO AVG)
DMR, Limited - Overdue
BOD, carbonaceous [5 day, 20 C]
0% over limit
Discharged 0 kg/d against a permitted limit of 1.40739999 kg/d (MO AVG)
DMR, Limited - Overdue
BOD, carbonaceous [5 day, 20 C]
0% over limit
Discharged 0 mg/L against a permitted limit of 25 mg/L (MO AVG)
DMR, Limited - Overdue
Nitrogen, ammonia total [as N]
0% over limit
Discharged 0 mg/L against a permitted limit of 5.2 mg/L (MO AVG)
DMR, Limited - Overdue
Coliform, fecal general
0% over limit
Discharged 0 MPN/100mL against a permitted limit of 10000 MPN/100mL (INST MAX)
DMR, Limited - Overdue
Chlorine, total residual
0% over limit
Discharged 0 mg/L against a permitted limit of 0.27 mg/L (MO AVG)
DMR, Limited - Overdue
pH
0% over limit
Discharged 0 SU against a permitted limit of 9 SU (INST MAX)
DMR, Limited - Overdue
Solids, total suspended
0% over limit
Discharged 0 kg/d against a permitted limit of 0 kg/d (DAILY MX)
DMR, Monitor Only - Overdue
BOD, carbonaceous [5 day, 20 C]
0% over limit
Discharged 0 kg/d against a permitted limit of 2.26999998 kg/d (DAILY MX)
DMR, Limited - Overdue
BOD, carbonaceous [5 day, 20 C]
0% over limit
Discharged 0 mg/L against a permitted limit of 40 mg/L (WKLY AVG)
DMR, Limited - Overdue
Solids, total suspended
0% over limit
Discharged 0 kg/d against a permitted limit of 2.54239998 kg/d (WKLY AVG)
DMR, Limited - Overdue
Nitrogen, ammonia total [as N]
0% over limit
Discharged 0 kg/d against a permitted limit of 0.2951 kg/d (MO AVG)
DMR, Limited - Overdue
February 28, 2026
BOD, carbonaceous [5 day, 20 C]
62% over limit
Discharged 3.67739997 kg/d against a permitted limit of 2.26999998 kg/d (DAILY MX)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
77% over limit
Discharged 2.49699998 kg/d against a permitted limit of 1.40739999 kg/d (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
36% over limit
Discharged 7.05 mg/L against a permitted limit of 5.2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
869% over limit
Discharged 2.86019998 kg/d against a permitted limit of 0.2951 kg/d (MO AVG)
DMR, Limited - Numeric Violation
January 31, 2026
Solids, total suspended
5% over limit
Discharged 1.81599998 kg/d against a permitted limit of 1.72519999 kg/d (MO AVG)
DMR, Limited - Numeric Violation
November 30, 2025
Nitrogen, ammonia total [as N]
25% over limit
Discharged 0.36774 kg/d against a permitted limit of 0.2951 kg/d (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
115% over limit
Discharged 11.2 mg/L against a permitted limit of 5.2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
May 31, 2025
Coliform, fecal general
142% over limit
Discharged 2419.6 MPN/100mL against a permitted limit of 1000 MPN/100mL (INST MAX)
DMR, Limited - Numeric Violation
Coliform, fecal general
357% over limit
Discharged 913 MPN/100mL against a permitted limit of 200 MPN/100mL (GEO MEAN)
DMR, Limited - Numeric Violation
April 30, 2025
Nitrogen, ammonia total [as N]
115% over limit
Discharged 11.2 mg/L against a permitted limit of 5.2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
28% over limit
Discharged 0.37682 kg/d against a permitted limit of 0.2951 kg/d (MO AVG)
DMR, Limited - Numeric Violation
March 31, 2025
Nitrogen, ammonia total [as N]
152% over limit
Discharged 13.1 mg/L against a permitted limit of 5.2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
85% over limit
Discharged 0.5448 kg/d against a permitted limit of 0.2951 kg/d (MO AVG)
DMR, Limited - Numeric Violation
February 28, 2025
Nitrogen, ammonia total [as N]
346% over limit
Discharged 23.2 mg/L against a permitted limit of 5.2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
177% over limit
Discharged 0.81719999 kg/d against a permitted limit of 0.2951 kg/d (MO AVG)
DMR, Limited - Numeric Violation
January 31, 2025
Nitrogen, ammonia total [as N]
22% over limit
Discharged 0.35866 kg/d against a permitted limit of 0.2951 kg/d (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
94% over limit
Discharged 10.1 mg/L against a permitted limit of 5.2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
December 31, 2024
Nitrogen, ammonia total [as N]
102% over limit
Discharged 10.5 mg/L against a permitted limit of 5.2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
51% over limit
Discharged 0.44492 kg/d against a permitted limit of 0.2951 kg/d (MO AVG)
DMR, Limited - Numeric Violation
November 30, 2024
Nitrogen, ammonia total [as N]
17% over limit
Discharged 0.34504 kg/d against a permitted limit of 0.2951 kg/d (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
129% over limit
Discharged 11.9 mg/L against a permitted limit of 5.2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
September 30, 2024
Coliform, fecal general
1% over limit
Discharged 1011.2 MPN/100mL against a permitted limit of 1000 MPN/100mL (INST MAX)
DMR, Limited - Numeric Violation
First flagged
April 14, 2026 (3 months ago)
Last confirmed
July 13, 2026 (22 days ago)