SANBORN CITY OF STP
NPDES ID: IA0032522
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: 9 effluent violations.
Violations
May 31, 2026
Nitrogen, ammonia total [as N]
144% over limit
Discharged 7.8 mg/L against a permitted limit of 3.2 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
204% over limit
Discharged 36.37949639 kg/d against a permitted limit of 11.9855999 kg/d (DAILY MX)
DMR, Limited - Numeric Violation
Oxygen, dissolved [DO]
4% over limit
Discharged 4.8 mg/L against a permitted limit of 5 mg/L (DAILY MN)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
296% over limit
Discharged 25.7120083 kg/d against a permitted limit of 6.49219995 kg/d (30DA AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
232% over limit
Discharged 5.6425 mg/L against a permitted limit of 1.7 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
April 30, 2026
Solids, total suspended
48% over limit
Discharged 44.28571 mg/L against a permitted limit of 30 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
44% over limit
Discharged 64.8 mg/L against a permitted limit of 45 mg/L (7 DA AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
61% over limit
Discharged 179.91429649 kg/d against a permitted limit of 111.68399906 kg/d (30DA AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
56% over limit
Discharged 261.4970062 kg/d against a permitted limit of 167.52599859 kg/d (7 DA AVG)
DMR, Limited - Numeric Violation
March 31, 2026
Nitrogen, ammonia total [as N]
74% over limit
Discharged 6.79 mg/L against a permitted limit of 3.9 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Solids, total suspended
5% over limit
Discharged 31.52272 mg/L against a permitted limit of 30 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
35% over limit
Discharged 17.15830788 kg/d against a permitted limit of 12.66659989 kg/d (30DA AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
20% over limit
Discharged 133.64343408 kg/d against a permitted limit of 111.68399906 kg/d (30DA AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
139% over limit
Discharged 34.56369163 kg/d against a permitted limit of 14.48259988 kg/d (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
11% over limit
Discharged 3.776666 mg/L against a permitted limit of 3.4 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
February 28, 2026
Nitrogen, ammonia total [as N]
141% over limit
Discharged 7.7 mg/L against a permitted limit of 3.2 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Solids, total suspended
35% over limit
Discharged 150.89320933 kg/d against a permitted limit of 111.68399906 kg/d (30DA AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
231% over limit
Discharged 39.47583085 kg/d against a permitted limit of 11.9401999 kg/d (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
113% over limit
Discharged 6.813333 mg/L against a permitted limit of 3.2 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
192% over limit
Discharged 34.84278813 kg/d against a permitted limit of 11.9401999 kg/d (30DA AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
0% over limit
Discharged 168.17176819 kg/d against a permitted limit of 167.52599859 kg/d (7 DA AVG)
DMR, Limited - Numeric Violation
December 31, 2025
Nitrogen, ammonia total [as N]
184% over limit
Discharged 26.1315497 kg/d against a permitted limit of 9.21619992 kg/d (30DA AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
136% over limit
Discharged 9.19 mg/L against a permitted limit of 3.9 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
200% over limit
Discharged 7.507 mg/L against a permitted limit of 2.5 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
130% over limit
Discharged 33.19497698 kg/d against a permitted limit of 14.43719988 kg/d (DAILY MX)
DMR, Limited - Numeric Violation
November 30, 2025
Nitrogen, ammonia total [as N]
23% over limit
Discharged 4.81 mg/L against a permitted limit of 3.9 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
31% over limit
Discharged 3.01125 mg/L against a permitted limit of 2.3 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
12% over limit
Discharged 9.6934765 kg/d against a permitted limit of 8.62599993 kg/d (30DA AVG)
DMR, Limited - Numeric Violation
October 31, 2025
Nitrogen, ammonia total [as N]
48% over limit
Discharged 8.57643221 kg/d against a permitted limit of 5.81119995 kg/d (30DA AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
38% over limit
Discharged 2.2125 mg/L against a permitted limit of 1.6 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
August 31, 2025
Nitrogen, ammonia total [as N]
111% over limit
Discharged 25.15431471 kg/d against a permitted limit of 11.9401999 kg/d (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
436% over limit
Discharged 5.35875 mg/L against a permitted limit of 1 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
531% over limit
Discharged 22.35144585 kg/d against a permitted limit of 3.54119997 kg/d (30DA AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
91% over limit
Discharged 6.11 mg/L against a permitted limit of 3.2 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
July 31, 2025
Nitrogen, ammonia total [as N]
150% over limit
Discharged 29.90773553 kg/d against a permitted limit of 11.9401999 kg/d (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
469% over limit
Discharged 5.69 mg/L against a permitted limit of 1 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
136% over limit
Discharged 7.55 mg/L against a permitted limit of 3.2 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
541% over limit
Discharged 23.85611988 kg/d against a permitted limit of 3.72279997 kg/d (30DA AVG)
DMR, Limited - Numeric Violation
June 30, 2025
pH
0% over limit
Discharged 7.2 SU against a permitted limit of 6.5 SU (DAILY MN)
DMR, Limited - Overdue
pH
0% over limit
Discharged 8.2 SU against a permitted limit of 9 SU (DAILY MX)
DMR, Limited - Overdue
BOD, carbonaceous [5 day, 20 C]
0% over limit
Discharged 6.668333 mg/L against a permitted limit of 25 mg/L (30DA AVG)
DMR, Limited - Overdue
Sulfate, total [as SO4]
0% over limit
Discharged 2938.09003131 kg/d against a permitted limit of 6937.11994171 kg/d (30DA AVG)
DMR, Limited - Overdue
BOD, carbonaceous [5 day, 20 C]
0% over limit
Discharged 7.965 mg/L against a permitted limit of 40 mg/L (7 DA AVG)
DMR, Limited - Overdue
BOD, carbonaceous [5 day, 20 C]
0% over limit
Discharged 17.89855487 kg/d against a permitted limit of 93.06999922 kg/d (30DA AVG)
DMR, Limited - Overdue
BOD, carbonaceous [5 day, 20 C]
0% over limit
Discharged 30.05797775 kg/d against a permitted limit of 148.91199875 kg/d (7 DA AVG)
DMR, Limited - Overdue
Sulfate, total [as SO4]
0% over limit
Discharged 830 mg/L against a permitted limit of 1864 mg/L (DAILY MX)
DMR, Limited - Overdue
Nitrogen, ammonia total [as N]
281% over limit
Discharged 37.53939374 kg/d against a permitted limit of 9.85179992 kg/d (DAILY MX)
DMR, Limited - Overdue
Nitrogen, ammonia total [as N]
281% over limit
Discharged 37.53939374 kg/d against a permitted limit of 9.85179992 kg/d (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
321% over limit
Discharged 20.42901011 kg/d against a permitted limit of 4.85779996 kg/d (30DA AVG)
DMR, Limited - Overdue
Nitrogen, ammonia total [as N]
321% over limit
Discharged 20.42901011 kg/d against a permitted limit of 4.85779996 kg/d (30DA AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
0% over limit
Discharged 25.68586698 kg/d against a permitted limit of 111.68399906 kg/d (30DA AVG)
DMR, Limited - Overdue
Solids, total suspended
0% over limit
Discharged 9.35 mg/L against a permitted limit of 30 mg/L (30DA AVG)
DMR, Limited - Overdue
Nitrogen, ammonia total [as N]
447% over limit
Discharged 7.115 mg/L against a permitted limit of 1.3 mg/L (30DA AVG)
DMR, Limited - Overdue
Nitrogen, ammonia total [as N]
447% over limit
Discharged 7.115 mg/L against a permitted limit of 1.3 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
Sulfate, total [as SO4]
0% over limit
Discharged 830 mg/L against a permitted limit of 1864 mg/L (30DA AVG)
DMR, Limited - Overdue
E. coli
0% over limit
Discharged 22.72622 MPN/100mL against a permitted limit of 800 MPN/100mL (GEO MEAN)
DMR, Limited - Overdue
Oxygen, dissolved [DO]
0% over limit
Discharged 5.1 mg/L against a permitted limit of 5 mg/L (DAILY MN)
DMR, Limited - Overdue
Nitrogen, ammonia total [as N]
249% over limit
Discharged 9.41 mg/L against a permitted limit of 2.7 mg/L (DAILY MX)
DMR, Limited - Overdue
Nitrogen, ammonia total [as N]
249% over limit
Discharged 9.41 mg/L against a permitted limit of 2.7 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Solids, total suspended
0% over limit
Discharged 42.57629216 kg/d against a permitted limit of 167.52599859 kg/d (7 DA AVG)
DMR, Limited - Overdue
Sulfate, total [as SO4]
0% over limit
Discharged 2938.09003131 kg/d against a permitted limit of 6937.11994171 kg/d (DAILY MX)
DMR, Limited - Overdue
Solids, total suspended
0% over limit
Discharged 11.83333 mg/L against a permitted limit of 45 mg/L (7 DA AVG)
DMR, Limited - Overdue
April 30, 2025
Solids, total suspended
13% over limit
Discharged 126.58713914 kg/d against a permitted limit of 111.68399906 kg/d (30DA AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
75% over limit
Discharged 78.625 mg/L against a permitted limit of 45 mg/L (7 DA AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
15% over limit
Discharged 193.18398998 kg/d against a permitted limit of 167.52599859 kg/d (7 DA AVG)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
31% over limit
Discharged 32.82 mg/L against a permitted limit of 25 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
87% over limit
Discharged 56 mg/L against a permitted limit of 30 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
2% over limit
Discharged 40.8 mg/L against a permitted limit of 40 mg/L (7 DA AVG)
DMR, Limited - Numeric Violation
March 31, 2025
Solids, total suspended
17% over limit
Discharged 35.22222 mg/L against a permitted limit of 30 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
6% over limit
Discharged 118.06242661 kg/d against a permitted limit of 111.68399906 kg/d (30DA AVG)
DMR, Limited - Numeric Violation
February 28, 2025
Nitrogen, ammonia total [as N]
10% over limit
Discharged 3.525 mg/L against a permitted limit of 3.2 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
24% over limit
Discharged 3.96 mg/L against a permitted limit of 3.2 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
21% over limit
Discharged 14.39272604 kg/d against a permitted limit of 11.9401999 kg/d (DAILY MX)
DMR, Limited - Numeric Violation
Solids, total suspended
12% over limit
Discharged 33.5 mg/L against a permitted limit of 30 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
January 31, 2025
Nitrogen, ammonia total [as N]
46% over limit
Discharged 4.955 mg/L against a permitted limit of 3.4 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
54% over limit
Discharged 19.49991274 kg/d against a permitted limit of 12.66659989 kg/d (30DA AVG)
DMR, Limited - Numeric Violation
December 31, 2024
Nitrogen, ammonia total [as N]
137% over limit
Discharged 5.913333 mg/L against a permitted limit of 2.5 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
160% over limit
Discharged 23.96599242 kg/d against a permitted limit of 9.21619992 kg/d (30DA AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
81% over limit
Discharged 26.18684236 kg/d against a permitted limit of 14.43719988 kg/d (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
59% over limit
Discharged 6.2 mg/L against a permitted limit of 3.9 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
October 31, 2024
Nitrogen, ammonia total [as N]
2% over limit
Discharged 5.94197919 kg/d against a permitted limit of 5.81119995 kg/d (30DA AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
85% over limit
Discharged 2.963333 mg/L against a permitted limit of 1.6 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
August 31, 2024
Nitrogen, ammonia total [as N]
127% over limit
Discharged 7.26 mg/L against a permitted limit of 3.2 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
67% over limit
Discharged 19.95424415 kg/d against a permitted limit of 11.9401999 kg/d (DAILY MX)
DMR, Limited - Numeric Violation
Solids, total suspended
12% over limit
Discharged 33.66666 mg/L against a permitted limit of 30 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
284% over limit
Discharged 13.61034331 kg/d against a permitted limit of 3.54119997 kg/d (30DA AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
350% over limit
Discharged 4.5 mg/L against a permitted limit of 1 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
July 31, 2024
Nitrogen, ammonia total [as N]
13% over limit
Discharged 13.46574431 kg/d against a permitted limit of 11.9401999 kg/d (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
28% over limit
Discharged 4.11 mg/L against a permitted limit of 3.2 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
148% over limit
Discharged 9.23149518 kg/d against a permitted limit of 3.72279997 kg/d (30DA AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
215% over limit
Discharged 3.148 mg/L against a permitted limit of 1 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
First flagged
April 14, 2026 (3 months ago)
Last confirmed
July 13, 2026 (24 days ago)