MCLEAN STW
NPDES ID: ILG580162
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.
Violations
April 30, 2026
Solids, total suspended
42% over limit
Discharged 64 mg/L against a permitted limit of 45 mg/L (WKLY AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
73% over limit
Discharged 64 mg/L against a permitted limit of 37 mg/L (MO AVG)
DMR, Limited - Numeric Violation
February 28, 2026
Solids, total suspended
97% over limit
Discharged 73 mg/L against a permitted limit of 37 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
62% over limit
Discharged 73 mg/L against a permitted limit of 45 mg/L (WKLY AVG)
DMR, Limited - Numeric Violation
January 31, 2026
Solids, total suspended
40% over limit
Discharged 63 mg/L against a permitted limit of 45 mg/L (WKLY AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
70% over limit
Discharged 63 mg/L against a permitted limit of 37 mg/L (MO AVG)
DMR, Limited - Numeric Violation
December 31, 2025
Solids, total suspended
31% over limit
Discharged 59 mg/L against a permitted limit of 45 mg/L (WKLY AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
59% over limit
Discharged 59 mg/L against a permitted limit of 37 mg/L (MO AVG)
DMR, Limited - Numeric Violation
November 30, 2025
Flow, in conduit or thru treatment plant
0% over limit
Discharged 0.07 MGD against a permitted limit of 0 MGD (MO AVG)
DMR, Monitor Only - Overdue
BOD, carbonaceous [5 day, 20 C]
0% over limit
Discharged 1.24849999 kg/d against a permitted limit of 48.57799959 kg/d (MO AVG)
DMR, Limited - Overdue
BOD, carbonaceous [5 day, 20 C]
0% over limit
Discharged 1.24849999 kg/d against a permitted limit of 77.63399935 kg/d (WKLY AVG)
DMR, Limited - Overdue
Solids, total suspended
0% over limit
Discharged 28 mg/L against a permitted limit of 45 mg/L (WKLY AVG)
DMR, Limited - Overdue
BOD, carbonaceous [5 day, 20 C]
0% over limit
Discharged 11 mg/L against a permitted limit of 40 mg/L (WKLY AVG)
DMR, Limited - Overdue
Nitrogen, ammonia total [as N]
0% over limit
Discharged 2.8 mg/L against a permitted limit of 0 mg/L (DAILY MX)
DMR, Monitor Only - Overdue
Oxygen, dissolved [DO]
0% over limit
Discharged 8.2 mg/L against a permitted limit of 6 mg/L (DAILY MN)
DMR, Limited - Overdue
Flow, in conduit or thru treatment plant
0% over limit
Discharged 0.03 MGD against a permitted limit of 0 MGD (DAILY MX)
DMR, Monitor Only - Overdue
Solids, total suspended
0% over limit
Discharged 3.17799997 kg/d against a permitted limit of 71.7319994 kg/d (MO AVG)
DMR, Limited - Overdue
pH
0% over limit
Discharged 8.25 SU against a permitted limit of 6 SU (MINIMUM)
DMR, Limited - Overdue
BOD, carbonaceous [5 day, 20 C]
0% over limit
Discharged 11 mg/L against a permitted limit of 25 mg/L (MO AVG)
DMR, Limited - Overdue
pH
0% over limit
Discharged 8.25 SU against a permitted limit of 9 SU (MAXIMUM)
DMR, Limited - Overdue
Flow, in conduit or thru treatment plant
0% over limit
Discharged 0.25 MGD against a permitted limit of 0 MGD (DAILY MX)
DMR, Monitor Only - Overdue
Solids, total suspended
0% over limit
Discharged 190 mg/L against a permitted limit of 0 mg/L (MO AVG)
DMR, Monitor Only - Overdue
Solids, total suspended
0% over limit
Discharged 28 mg/L against a permitted limit of 37 mg/L (MO AVG)
DMR, Limited - Overdue
Solids, total suspended
0% over limit
Discharged 3.17799997 kg/d against a permitted limit of 87.62199926 kg/d (WKLY AVG)
DMR, Limited - Overdue
Flow, in conduit or thru treatment plant
0% over limit
Discharged 0.03 MGD against a permitted limit of 0 MGD (MO AVG)
DMR, Monitor Only - Overdue
BOD, 5-day, 20 deg. C
0% over limit
Discharged 37 mg/L against a permitted limit of 0 mg/L (MO AVG)
DMR, Monitor Only - Overdue
October 31, 2025
Solids, total suspended
20% over limit
Discharged 54 mg/L against a permitted limit of 45 mg/L (WKLY AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
46% over limit
Discharged 54 mg/L against a permitted limit of 37 mg/L (MO AVG)
DMR, Limited - Numeric Violation
September 30, 2025
pH
0% over limit
Discharged 9.1 SU against a permitted limit of 9 SU (MAXIMUM)
DMR, Limited - Numeric Violation
August 31, 2025
Solids, total suspended
8% over limit
Discharged 40 mg/L against a permitted limit of 37 mg/L (MO AVG)
DMR, Limited - Numeric Violation
July 31, 2025
Solids, total suspended
11% over limit
Discharged 50 mg/L against a permitted limit of 45 mg/L (WKLY AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
35% over limit
Discharged 50 mg/L against a permitted limit of 37 mg/L (MO AVG)
DMR, Limited - Numeric Violation
June 30, 2025
pH
0% over limit
Discharged 9.73 SU against a permitted limit of 9 SU (MAXIMUM)
DMR, Limited - Numeric Violation
May 31, 2025
Solids, total suspended
144% over limit
Discharged 110 mg/L against a permitted limit of 45 mg/L (WKLY AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
197% over limit
Discharged 110 mg/L against a permitted limit of 37 mg/L (MO AVG)
DMR, Limited - Numeric Violation
April 30, 2025
Solids, total suspended
3% over limit
Discharged 38 mg/L against a permitted limit of 37 mg/L (MO AVG)
DMR, Limited - Numeric Violation
February 28, 2025
Solids, total suspended
20% over limit
Discharged 54 mg/L against a permitted limit of 45 mg/L (WKLY AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
46% over limit
Discharged 54 mg/L against a permitted limit of 37 mg/L (MO AVG)
DMR, Limited - Numeric Violation
January 31, 2025
Solids, total suspended
5% over limit
Discharged 39 mg/L against a permitted limit of 37 mg/L (MO AVG)
DMR, Limited - Numeric Violation
October 31, 2024
Solids, total suspended
16% over limit
Discharged 43 mg/L against a permitted limit of 37 mg/L (MO AVG)
DMR, Limited - Numeric Violation
September 30, 2024
Solids, total suspended
41% over limit
Discharged 52 mg/L against a permitted limit of 37 mg/L (MO AVG)
DMR, Limited - Overdue
Solids, total suspended
41% over limit
Discharged 52 mg/L against a permitted limit of 37 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
0% over limit
Discharged 5.90199995 kg/d against a permitted limit of 87.62199926 kg/d (WKLY AVG)
DMR, Limited - Overdue
BOD, carbonaceous [5 day, 20 C]
0% over limit
Discharged 12 mg/L against a permitted limit of 40 mg/L (WKLY AVG)
DMR, Limited - Overdue
Oxygen, dissolved [DO]
0% over limit
Discharged 9.2 mg/L against a permitted limit of 6 mg/L (DAILY MN)
DMR, Limited - Overdue
Solids, total suspended
0% over limit
Discharged 5.90199995 kg/d against a permitted limit of 71.7319994 kg/d (MO AVG)
DMR, Limited - Overdue
Flow, in conduit or thru treatment plant
0% over limit
Discharged 0.09 MGD against a permitted limit of 0 MGD (MO AVG)
DMR, Monitor Only - Overdue
BOD, 5-day, 20 deg. C
0% over limit
Discharged 180 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 1.1 mg/L against a permitted limit of 0 mg/L (DAILY MX)
DMR, Monitor Only - Overdue
Solids, total suspended
0% over limit
Discharged 140 mg/L against a permitted limit of 0 mg/L (MO AVG)
DMR, Monitor Only - Overdue
Coliform, fecal general
0% over limit
Discharged 88 MPN/100mL against a permitted limit of 0 MPN/100mL (DAILY MX)
DMR, Monitor Only - Overdue
pH
0% over limit
Discharged 8.81 SU against a permitted limit of 9 SU (MAXIMUM)
DMR, Limited - Overdue
BOD, carbonaceous [5 day, 20 C]
0% over limit
Discharged 12 mg/L against a permitted limit of 25 mg/L (MO AVG)
DMR, Limited - Overdue
Flow, in conduit or thru treatment plant
0% over limit
Discharged 0.03 MGD against a permitted limit of 0 MGD (DAILY MX)
DMR, Monitor Only - Overdue
Solids, total suspended
16% over limit
Discharged 52 mg/L against a permitted limit of 45 mg/L (WKLY AVG)
DMR, Limited - Overdue
Solids, total suspended
16% over limit
Discharged 52 mg/L against a permitted limit of 45 mg/L (WKLY AVG)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
0% over limit
Discharged 1.36199999 kg/d against a permitted limit of 77.63399935 kg/d (WKLY AVG)
DMR, Limited - Overdue
BOD, carbonaceous [5 day, 20 C]
0% over limit
Discharged 1.36199999 kg/d against a permitted limit of 48.57799959 kg/d (MO AVG)
DMR, Limited - Overdue
pH
0% over limit
Discharged 8.81 SU against a permitted limit of 6 SU (MINIMUM)
DMR, Limited - Overdue
Flow, in conduit or thru treatment plant
0% over limit
Discharged 0.26 MGD against a permitted limit of 0 MGD (DAILY MX)
DMR, Monitor Only - Overdue
Flow, in conduit or thru treatment plant
0% over limit
Discharged 0.03 MGD against a permitted limit of 0 MGD (MO AVG)
DMR, Monitor Only - Overdue
August 31, 2024
Solids, total suspended
14% over limit
Discharged 42 mg/L against a permitted limit of 37 mg/L (MO AVG)
DMR, Limited - Numeric Violation
July 31, 2024
Solids, total suspended
5% over limit
Discharged 39 mg/L against a permitted limit of 37 mg/L (MO AVG)
DMR, Limited - Numeric Violation
First flagged
April 14, 2026 (3 months ago)
Last confirmed
July 13, 2026 (23 days ago)