ROCKWELL CITY, CITY OF STP
NPDES ID: IA0033138
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: 5 effluent violations.
Violations
May 31, 2026
Chloride [as Cl]
76% over limit
Discharged 712 mg/L against a permitted limit of 405 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
Chloride [as Cl]
13% over limit
Discharged 712 mg/L against a permitted limit of 632 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
April 30, 2026
Chloride [as Cl]
4% over limit
Discharged 657 mg/L against a permitted limit of 632 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Chloride [as Cl]
62% over limit
Discharged 657 mg/L against a permitted limit of 405 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
E. coli
129% over limit
Discharged 288.2902 MPN/100mL against a permitted limit of 126 MPN/100mL (GEO MEAN)
DMR, Limited - Numeric Violation
March 31, 2026
Copper, total [as Cu]
195% over limit
Discharged 0.052 mg/L against a permitted limit of 0.01765 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
Chloride [as Cl]
39% over limit
Discharged 877 mg/L against a permitted limit of 632 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Copper, total [as Cu]
92% over limit
Discharged 0.052 mg/L against a permitted limit of 0.02702 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Chloride [as Cl]
117% over limit
Discharged 877 mg/L against a permitted limit of 405 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
February 28, 2026
Solids, total suspended
138% over limit
Discharged 107 mg/L against a permitted limit of 45 mg/L (7 DA AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
30% over limit
Discharged 39.075 mg/L against a permitted limit of 30 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
Chloride [as Cl]
44% over limit
Discharged 582 mg/L against a permitted limit of 405 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
January 31, 2026
Solids, total suspended
11% over limit
Discharged 50 mg/L against a permitted limit of 45 mg/L (7 DA AVG)
DMR, Limited - Numeric Violation
Chloride [as Cl]
45% over limit
Discharged 587 mg/L against a permitted limit of 405 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
September 30, 2025
Solids, total suspended
91% over limit
Discharged 57.2 mg/L against a permitted limit of 30 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
353% over limit
Discharged 204 mg/L against a permitted limit of 45 mg/L (7 DA AVG)
DMR, Limited - Numeric Violation
January 31, 2025
Solids, total suspended
4% over limit
Discharged 47 mg/L against a permitted limit of 45 mg/L (7 DA AVG)
DMR, Limited - Numeric Violation
December 31, 2024
Nitrogen, ammonia total [as N]
13% over limit
Discharged 7.439 mg/L against a permitted limit of 6.6 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Solids, total suspended
109% over limit
Discharged 62.75 mg/L against a permitted limit of 30 mg/L (30DA AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
3% over limit
Discharged 196.39849155 kg/d against a permitted limit of 189.77199841 kg/d (7 DA AVG)
DMR, Limited - Numeric Violation
Solids, total suspended
367% over limit
Discharged 210 mg/L against a permitted limit of 45 mg/L (7 DA AVG)
DMR, Limited - Numeric Violation
First flagged
April 14, 2026 (3 months ago)
Last confirmed
July 13, 2026 (23 days ago)