OAK HILL WWTP
NPDES ID: MO0127701
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
May 31, 2026
Nitrogen, ammonia total [as N]
186% over limit
Discharged 6.3 mg/L against a permitted limit of 2.2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
April 30, 2026
Nitrogen, ammonia total [as N]
100% over limit
Discharged 5.39 mg/L against a permitted limit of 2.7 mg/L (MO AVG)
DMR, Limited - Numeric Violation
March 31, 2026
Nitrogen, ammonia total [as N]
19% over limit
Discharged 3.7 mg/L against a permitted limit of 3.1 mg/L (MO AVG)
DMR, Limited - Numeric Violation
February 28, 2026
Nitrogen, ammonia total [as N]
70% over limit
Discharged 4.6 mg/L against a permitted limit of 2.7 mg/L (MO AVG)
DMR, Limited - Numeric Violation
December 31, 2025
Nitrogen, ammonia total [as N]
435% over limit
Discharged 16.6 mg/L against a permitted limit of 3.1 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
37% over limit
Discharged 16.6 mg/L against a permitted limit of 12.1 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
November 30, 2025
Nitrogen, ammonia total [as N]
487% over limit
Discharged 18.2 mg/L against a permitted limit of 3.1 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
50% over limit
Discharged 18.2 mg/L against a permitted limit of 12.1 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
August 31, 2025
pH
0% over limit
Discharged 5.51 SU against a permitted limit of 6.5 SU (MINIMUM)
DMR, Limited - Numeric Violation
Phosphorus, total [as P]
22% over limit
Discharged 0.61 mg/L against a permitted limit of 0.5 mg/L (MO AVG)
DMR, Limited - Numeric Violation
July 31, 2025
Phosphorus, total [as P]
18% over limit
Discharged 0.59 mg/L against a permitted limit of 0.5 mg/L (MO AVG)
DMR, Limited - Numeric Violation
June 30, 2025
E. coli
702% over limit
Discharged 1011 MPN/100mL against a permitted limit of 126 MPN/100mL (30DA GM)
DMR, Limited - Numeric Violation
Chlorine, total residual
178% over limit
Discharged 50 mg/L against a permitted limit of 18 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
E. coli
60% over limit
Discharged 1011 MPN/100mL against a permitted limit of 630 MPN/100mL (DAILY MX)
DMR, Limited - Numeric Violation
Chlorine, total residual
456% over limit
Discharged 50 mg/L against a permitted limit of 9 mg/L (MO AVG)
DMR, Limited - Numeric Violation
March 31, 2025
Aluminum, total recoverable
0% over limit
Discharged 0 mg/L against a permitted limit of 0.75000004 mg/L (DAILY MX)
DMR, Limited - Overdue
Aluminum, total recoverable
0% over limit
Discharged 0 mg/L against a permitted limit of 0.26093001 mg/L (MO AVG)
DMR, Limited - Overdue
February 28, 2025
Nitrogen, ammonia total [as N]
233% over limit
Discharged 33.6 mg/L against a permitted limit of 10.1 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
1144% over limit
Discharged 33.6 mg/L against a permitted limit of 2.7 mg/L (MO AVG)
DMR, Limited - Numeric Violation
January 31, 2025
Nitrogen, ammonia total [as N]
81% over limit
Discharged 5.62 mg/L against a permitted limit of 3.1 mg/L (MO AVG)
DMR, Limited - Numeric Violation
First flagged
April 14, 2026 (3 months ago)
Last confirmed
July 13, 2026 (24 days ago)