UNDERWOOD CITY OF STP
NPDES ID: IA0036986
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: 8 effluent violations.
Violations
May 31, 2026
BOD, carbonaceous [5 day, 20 C]
73% over limit
Discharged 43.35 mg/L against a permitted limit of 25 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
6% over limit
Discharged 26.15 mg/L against a permitted limit of 24.7 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
26% over limit
Discharged 50.5 mg/L against a permitted limit of 40 mg/L (7 DA AVG)
DMR, Limited - Numeric Violation
April 30, 2026
BOD, carbonaceous [5 day, 20 C]
24% over limit
Discharged 19.08255962 kg/d against a permitted limit of 15.43599987 kg/d (30DA AVG)
DMR, Limited - Numeric Violation
E. coli
284% over limit
Discharged 2419.6 MPN/100mL against a permitted limit of 630 MPN/100mL (GEO MEAN)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
109% over limit
Discharged 52.26 mg/L against a permitted limit of 25 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
55% over limit
Discharged 61.8 mg/L against a permitted limit of 40 mg/L (7 DA AVG)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
0% over limit
Discharged 24.98116365 kg/d against a permitted limit of 24.96999979 kg/d (7 DA AVG)
DMR, Limited - Numeric Violation
March 31, 2026
BOD, carbonaceous [5 day, 20 C]
181% over limit
Discharged 70.32 mg/L against a permitted limit of 25 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
96% over limit
Discharged 78.5 mg/L against a permitted limit of 40 mg/L (7 DA AVG)
DMR, Limited - Numeric Violation
February 28, 2026
BOD, carbonaceous [5 day, 20 C]
139% over limit
Discharged 59.8 mg/L against a permitted limit of 25 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
79% over limit
Discharged 71.7 mg/L against a permitted limit of 40 mg/L (7 DA AVG)
DMR, Limited - Numeric Violation
January 31, 2026
BOD, carbonaceous [5 day, 20 C]
39% over limit
Discharged 55.4 mg/L against a permitted limit of 40 mg/L (7 DA AVG)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
93% over limit
Discharged 48.225 mg/L against a permitted limit of 25 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
December 31, 2025
BOD, carbonaceous [5 day, 20 C]
29% over limit
Discharged 32.322 mg/L against a permitted limit of 25 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
November 30, 2025
BOD, carbonaceous [5 day, 20 C]
8% over limit
Discharged 43.1 mg/L against a permitted limit of 40 mg/L (7 DA AVG)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
44% over limit
Discharged 35.975 mg/L against a permitted limit of 25 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
First flagged
April 14, 2026 (3 months ago)
Last confirmed
July 13, 2026 (23 days ago)