CITY OF HARLOWTON WWTF
NPDES ID: MT0020354
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: 5 effluent violations.
Violations
June 30, 2026
Solids, total suspended
42% over limit
Discharged 64 mg/L against a permitted limit of 45 mg/L (MO AVG)
DMR, Limited - Numeric Violation
May 31, 2026
BOD, 5-day, 20 deg. C
7% over limit
Discharged 32 mg/L against a permitted limit of 30 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 (MO AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
12% over limit
Discharged 73 mg/L against a permitted limit of 65 mg/L (MX WK AV)
DMR, Limited - Numeric Violation
April 30, 2026
Solids, total suspended
18% over limit
Discharged 53 mg/L against a permitted limit of 45 mg/L (MO AVG)
DMR, Limited - Numeric Violation
December 31, 2025
Solids, total suspended
2% over limit
Discharged 46 mg/L against a permitted limit of 45 mg/L (MO AVG)
DMR, Limited - Numeric Violation
May 31, 2025
BOD, 5-day, 20 deg. C
0% over limit
Discharged 19.99415983 kg/d against a permitted limit of 24.96999979 kg/d (MO AVG)
DMR, Limited - Overdue
BOD, 5-day, 20 deg. C
0% over limit
Discharged 19.99415983 kg/d against a permitted limit of 37.50039968 kg/d (MX WK AV)
DMR, Limited - Overdue
BOD, 5-day, 20 deg. C
47% over limit
Discharged 44 mg/L against a permitted limit of 30 mg/L (MO AVG)
DMR, Limited - Overdue
BOD, 5-day, 20 deg. C
47% over limit
Discharged 44 mg/L against a permitted limit of 30 mg/L (MO AVG)
DMR, Limited - Numeric Violation
E. coli, MTEC-MF
0% over limit
Discharged 2.51 MPN/100mL against a permitted limit of 126 MPN/100mL (MOAV GEO)
DMR, Limited - Overdue
Solids, total suspended
53% over limit
Discharged 69 mg/L against a permitted limit of 45 mg/L (MO AVG)
DMR, Limited - Overdue
Solids, total suspended
53% over limit
Discharged 69 mg/L against a permitted limit of 45 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
0% over limit
Discharged 31.35323974 kg/d against a permitted limit of 54.16219954 kg/d (MX WK AV)
DMR, Limited - Overdue
Solids, total suspended
0% over limit
Discharged 31.35323974 kg/d against a permitted limit of 37.50039968 kg/d (MO AVG)
DMR, Limited - Overdue
E. coli, MTEC-MF
0% over limit
Discharged 2.51 MPN/100mL against a permitted limit of 252 MPN/100mL (MX WK AV)
DMR, Limited - Overdue
BOD, 5-day, 20 deg. C
0% over limit
Discharged 44 mg/L against a permitted limit of 45 mg/L (MX WK AV)
DMR, Limited - Overdue
Solids, total suspended
6% over limit
Discharged 69 mg/L against a permitted limit of 65 mg/L (MX WK AV)
DMR, Limited - Overdue
Solids, total suspended
6% over limit
Discharged 69 mg/L against a permitted limit of 65 mg/L (MX WK AV)
DMR, Limited - Numeric Violation
Flow rate
0% over limit
Discharged 0.14 MGD against a permitted limit of 0 MGD (DAILY MX)
DMR, Monitor Only - Overdue
November 30, 2024
pH
0% over limit
Discharged 9.5 SU against a permitted limit of 9 SU (DAILY MX)
DMR, Limited - Numeric Violation
October 31, 2024
pH
0% over limit
Discharged 9.6 SU against a permitted limit of 9 SU (DAILY MX)
DMR, Limited - Numeric Violation
September 30, 2024
pH
0% over limit
Discharged 0 SU against a permitted limit of 9 SU (DAILY MX)
DMR, Limited - Overdue
pH
0% over limit
Discharged 0 SU against a permitted limit of 6 SU (DAILY MN)
DMR, Limited - Overdue
August 31, 2024
Solids, total suspended
4% over limit
Discharged 47 mg/L against a permitted limit of 45 mg/L (MO AVG)
DMR, Limited - Numeric Violation
pH
0% over limit
Discharged 9.61 SU against a permitted limit of 9 SU (DAILY MX)
DMR, Limited - Numeric Violation
First flagged
April 14, 2026 (4 months ago)
Last confirmed
August 17, 2026 (4 hours ago)