ORONOCO WWTP
NPDES ID: MN0071421
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: 1 effluent violation, 2 reporting violations.
Violations
May 31, 2026
Nitrogen, total [as N]
10% over limit
Discharged 11 mg/L against a permitted limit of 10 mg/L (MO AVG)
DMR, Limited - Numeric Violation
March 31, 2026
Nitrogen, total [as N]
0% over limit
Discharged 0 mg/L against a permitted limit of 10 mg/L (MO AVG)
DMR, Limited - Overdue
Nitrogen, total [as N]
125% over limit
Discharged 22.5 mg/L against a permitted limit of 10 mg/L (MO AVG)
DMR, Limited - Numeric Violation
February 28, 2026
Nitrogen, total [as N]
0% over limit
Discharged 0 mg/L against a permitted limit of 10 mg/L (MO AVG)
DMR, Limited - Overdue
Nitrogen, total [as N]
177% over limit
Discharged 27.7 mg/L against a permitted limit of 10 mg/L (MO AVG)
DMR, Limited - Numeric Violation
pH
0% over limit
Discharged 5.4 SU against a permitted limit of 6 SU (MO MIN)
DMR, Limited - Numeric Violation
January 31, 2026
Nitrogen, total [as N]
0% over limit
Discharged 0 mg/L against a permitted limit of 10 mg/L (MO AVG)
DMR, Limited - Overdue
Nitrogen, total [as N]
197% over limit
Discharged 29.7 mg/L against a permitted limit of 10 mg/L (MO AVG)
DMR, Limited - Numeric Violation
December 31, 2025
Nitrogen, total [as N]
0% over limit
Discharged 0 mg/L against a permitted limit of 10 mg/L (MO AVG)
DMR, Limited - Overdue
Nitrogen, total [as N]
53% over limit
Discharged 15.3 mg/L against a permitted limit of 10 mg/L (MO AVG)
DMR, Limited - Numeric Violation
November 30, 2025
Nitrogen, total [as N]
0% over limit
Discharged 0 mg/L against a permitted limit of 10 mg/L (MO AVG)
DMR, Limited - Overdue
Nitrogen, total [as N]
10% over limit
Discharged 11 mg/L against a permitted limit of 10 mg/L (MO AVG)
DMR, Limited - Numeric Violation
October 31, 2025
Nitrogen, total [as N]
0% over limit
Discharged 0 mg/L against a permitted limit of 10 mg/L (MO AVG)
DMR, Limited - Overdue
April 30, 2025
Nitrogen, total [as N]
7% over limit
Discharged 10.7 mg/L against a permitted limit of 10 mg/L (MO AVG)
DMR, Limited - Numeric Violation
March 31, 2025
Phosphorus, total [as P]
150% over limit
Discharged 1 mg/L against a permitted limit of 0.4 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Solids, total dissolved
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (MO AVG)
DMR, Monitor Only - Overdue
February 28, 2025
Nitrogen, total [as N]
141% over limit
Discharged 24.1 mg/L against a permitted limit of 10 mg/L (MO AVG)
DMR, Limited - Numeric Violation
January 31, 2025
Nitrogen, total [as N]
226% over limit
Discharged 32.6 mg/L against a permitted limit of 10 mg/L (MO AVG)
DMR, Limited - Numeric Violation
December 31, 2024
Nitrogen, total [as N]
157% over limit
Discharged 25.7 mg/L against a permitted limit of 10 mg/L (MO AVG)
DMR, Limited - Numeric Violation
November 30, 2024
Phosphorus, total [as P]
200% over limit
Discharged 1.2 mg/L against a permitted limit of 0.4 mg/L (MO AVG)
DMR, Limited - Numeric Violation
October 31, 2024
Phosphorus, total [as P]
375% over limit
Discharged 1.9 mg/L against a permitted limit of 0.4 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, total [as N]
28% over limit
Discharged 12.8 mg/L against a permitted limit of 10 mg/L (MO AVG)
DMR, Limited - Numeric Violation
September 30, 2024
Nitrogen, total [as N]
88% over limit
Discharged 18.8 mg/L against a permitted limit of 10 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Solids, total dissolved
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (MO AVG)
DMR, Monitor Only - Overdue
Phosphorus, total [as P]
300% over limit
Discharged 1.6 mg/L against a permitted limit of 0.4 mg/L (MO AVG)
DMR, Limited - Numeric Violation
August 31, 2024
Phosphorus, total [as P]
75% over limit
Discharged 0.7 mg/L against a permitted limit of 0.4 mg/L (MO AVG)
DMR, Limited - Numeric Violation
July 31, 2024
Nitrogen, total [as N]
14% over limit
Discharged 11.4 mg/L against a permitted limit of 10 mg/L (MO AVG)
DMR, Limited - Numeric Violation
First flagged
April 14, 2026 (3 months ago)
Last confirmed
July 13, 2026 (23 days ago)