LAKE MILLS CITY OF STP
NPDES ID: IA0027448
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: 6 effluent violations.
Violations
April 30, 2026
Nitrogen, ammonia total [as N]
166% over limit
Discharged 3.996042 mg/L against a permitted limit of 1.5 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
54% over limit
Discharged 6.642651 kg/d against a permitted limit of 4.31299996 kg/d (30DA AVG)
DMR, Limited - Numeric Violation
pH
0% over limit
Discharged 9.78 SU against a permitted limit of 9 SU (DAILY MX)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
22% over limit
Discharged 30.57142 mg/L against a permitted limit of 25 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
Oxygen, dissolved [DO]
82% over limit
Discharged 0.9 mg/L against a permitted limit of 5 mg/L (DAILY MN)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
46% over limit
Discharged 6.8646 mg/L against a permitted limit of 4.7 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
March 31, 2026
pH
0% over limit
Discharged 9.03 SU against a permitted limit of 9 SU (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
135% over limit
Discharged 9.1591 mg/L against a permitted limit of 3.9 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
111% over limit
Discharged 7.173877 mg/L against a permitted limit of 3.4 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
Oxygen, dissolved [DO]
56% over limit
Discharged 2.2 mg/L against a permitted limit of 5 mg/L (DAILY MN)
DMR, Limited - Numeric Violation
February 28, 2026
Oxygen, dissolved [DO]
26% over limit
Discharged 3.7 mg/L against a permitted limit of 5 mg/L (DAILY MN)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
10% over limit
Discharged 9.2532 mg/L against a permitted limit of 8.4 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
117% over limit
Discharged 8.682762 mg/L against a permitted limit of 4 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
January 31, 2026
Oxygen, dissolved [DO]
22% over limit
Discharged 3.9 mg/L against a permitted limit of 5 mg/L (DAILY MN)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
59% over limit
Discharged 5.404825 mg/L against a permitted limit of 3.4 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
December 31, 2025
Nitrogen, ammonia total [as N]
23% over limit
Discharged 3.06486 mg/L against a permitted limit of 2.5 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
November 30, 2025
Nitrogen, ammonia total [as N]
6% over limit
Discharged 2.427675 mg/L against a permitted limit of 2.3 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
25% over limit
Discharged 3.3843 mg/L against a permitted limit of 2.7 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
September 30, 2025
Oxygen, dissolved [DO]
28% over limit
Discharged 3.6 mg/L against a permitted limit of 5 mg/L (DAILY MN)
DMR, Limited - Numeric Violation
pH
0% over limit
Discharged 9.37 SU against a permitted limit of 9 SU (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
9% over limit
Discharged 2.9355 mg/L against a permitted limit of 2.7 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
August 31, 2025
pH
0% over limit
Discharged 9.58 SU against a permitted limit of 9 SU (DAILY MX)
DMR, Limited - Numeric Violation
Oxygen, dissolved [DO]
36% over limit
Discharged 3.2 mg/L against a permitted limit of 5 mg/L (DAILY MN)
DMR, Limited - Numeric Violation
July 31, 2025
Oxygen, dissolved [DO]
32% over limit
Discharged 3.4 mg/L against a permitted limit of 5 mg/L (DAILY MN)
DMR, Limited - Numeric Violation
pH
0% over limit
Discharged 9.91 SU against a permitted limit of 9 SU (DAILY MX)
DMR, Limited - Numeric Violation
June 30, 2025
Nitrogen, ammonia total [as N]
59% over limit
Discharged 2.06295 mg/L against a permitted limit of 1.3 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
21% over limit
Discharged 3.8721 mg/L against a permitted limit of 3.2 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
pH
0% over limit
Discharged 9.19 SU against a permitted limit of 9 SU (DAILY MX)
DMR, Limited - Numeric Violation
Oxygen, dissolved [DO]
12% over limit
Discharged 4.4 mg/L against a permitted limit of 5 mg/L (DAILY MN)
DMR, Limited - Numeric Violation
May 31, 2025
Nitrogen, ammonia total [as N]
104% over limit
Discharged 3.472687 mg/L against a permitted limit of 1.7 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
Oxygen, dissolved [DO]
30% over limit
Discharged 3.5 mg/L against a permitted limit of 5 mg/L (DAILY MN)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
3% over limit
Discharged 9.3540661 kg/d against a permitted limit of 9.07999992 kg/d (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
102% over limit
Discharged 6.4503 mg/L against a permitted limit of 3.2 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
April 30, 2025
pH
0% over limit
Discharged 9.14 SU against a permitted limit of 9 SU (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
1% over limit
Discharged 4.35190867 kg/d against a permitted limit of 4.31299996 kg/d (30DA AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
144% over limit
Discharged 3.66133 mg/L against a permitted limit of 1.5 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
19% over limit
Discharged 5.5807 mg/L against a permitted limit of 4.7 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
March 31, 2025
pH
0% over limit
Discharged 9.2 SU against a permitted limit of 9 SU (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
91% over limit
Discharged 7.46 mg/L against a permitted limit of 3.9 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
93% over limit
Discharged 6.565462 mg/L against a permitted limit of 3.4 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
February 28, 2025
pH
0% over limit
Discharged 9.03 SU against a permitted limit of 9 SU (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
15% over limit
Discharged 4.590125 mg/L against a permitted limit of 4 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
January 31, 2025
pH
0% over limit
Discharged 9.25 SU against a permitted limit of 9 SU (DAILY MX)
DMR, Limited - Numeric Violation
December 31, 2024
Nitrogen, ammonia total [as N]
40% over limit
Discharged 5.4555 mg/L against a permitted limit of 3.9 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
October 31, 2024
pH
0% over limit
Discharged 9.01 SU against a permitted limit of 9 SU (DAILY MX)
DMR, Limited - Numeric Violation
September 30, 2024
pH
0% over limit
Discharged 9.17 SU against a permitted limit of 9 SU (DAILY MX)
DMR, Limited - Numeric Violation
August 31, 2024
pH
0% over limit
Discharged 9.31 SU against a permitted limit of 9 SU (DAILY MX)
DMR, Limited - Numeric Violation
Oxygen, dissolved [DO]
10% over limit
Discharged 4.5 mg/L against a permitted limit of 5 mg/L (DAILY MN)
DMR, Limited - Numeric Violation
July 31, 2024
pH
0% over limit
Discharged 9.39 SU against a permitted limit of 9 SU (DAILY MX)
DMR, Limited - Numeric Violation
First flagged
April 14, 2026 (3 months ago)
Last confirmed
July 13, 2026 (24 days ago)