DYERSVILLE CITY OF STP
NPDES ID: IA0023345
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: 7 effluent violations.
Violations
May 31, 2026
Oxygen, dissolved [DO]
17% over limit
Discharged 2.25 mg/L against a permitted limit of 2.7 mg/L (DAILY MN)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
44% over limit
Discharged 57.5 mg/L against a permitted limit of 40 mg/L (7 DA AVG)
DMR, Limited - Numeric Violation
April 30, 2026
Nitrogen, ammonia total [as N]
111% over limit
Discharged 12.25666 mg/L against a permitted limit of 5.8 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
36% over limit
Discharged 21.73533608 kg/d against a permitted limit of 15.93539987 kg/d (30DA AVG)
DMR, Limited - Numeric Violation
Oxygen, dissolved [DO]
94% over limit
Discharged 0.17 mg/L against a permitted limit of 2.7 mg/L (DAILY MN)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
6% over limit
Discharged 18.3 mg/L against a permitted limit of 17.2 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
First flagged
April 14, 2026 (5 months ago)
Last confirmed
September 15, 2026 (5 days ago)