CITY OF CASA GRANDE - WRF
NPDES ID: AZ0025178
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: 3 single-event violations.
Violations
February 28, 2026
Cyanide, total [as CN]
58% over limit
Discharged 0.0128 mg/L against a permitted limit of 0.0081 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Cyanide, total [as CN]
7% over limit
Discharged 0.016 mg/L against a permitted limit of 0.015 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
January 31, 2026
Flow, in conduit or thru treatment plant
0% over limit
Discharged 0 MGD against a permitted limit of 0 MGD (MO AVG)
DMR, Monitor Only - Overdue
Cyanide, total [as CN]
48% over limit
Discharged 0.012 mg/L against a permitted limit of 0.0081 mg/L (MO AVG)
DMR, Limited - Numeric Violation
December 31, 2025
Flow, in conduit or thru treatment plant
0% over limit
Discharged 0 MGD against a permitted limit of 0 MGD (MO AVG)
DMR, Monitor Only - Overdue
November 30, 2025
pH
0% over limit
Discharged 6.05 SU against a permitted limit of 6.5 SU (MINIMUM)
DMR, Limited - Numeric Violation
Flow, in conduit or thru treatment plant
0% over limit
Discharged 0 MGD against a permitted limit of 0 MGD (MO AVG)
DMR, Monitor Only - Overdue
October 31, 2025
Flow, in conduit or thru treatment plant
0% over limit
Discharged 0 MGD against a permitted limit of 0 MGD (MO AVG)
DMR, Monitor Only - Overdue
September 30, 2025
Flow, in conduit or thru treatment plant
0% over limit
Discharged 0 MGD against a permitted limit of 0 MGD (MO AVG)
DMR, Monitor Only - Overdue
August 31, 2025
Flow, in conduit or thru treatment plant
0% over limit
Discharged 0 MGD against a permitted limit of 0 MGD (MO AVG)
DMR, Monitor Only - Overdue
Cyanide, total [as CN]
48% over limit
Discharged 0.012 mg/L against a permitted limit of 0.0081 mg/L (MO AVG)
DMR, Limited - Numeric Violation
July 31, 2025
Flow, in conduit or thru treatment plant
0% over limit
Discharged 0 MGD against a permitted limit of 0 MGD (MO AVG)
DMR, Monitor Only - Overdue
June 30, 2025
Flow, in conduit or thru treatment plant
0% over limit
Discharged 0 MGD against a permitted limit of 0 MGD (MO AVG)
DMR, Monitor Only - Overdue
pH
0% over limit
Discharged 6.2 SU against a permitted limit of 6.5 SU (MINIMUM)
DMR, Limited - Numeric Violation
May 31, 2025
Flow, in conduit or thru treatment plant
0% over limit
Discharged 0 MGD against a permitted limit of 0 MGD (MO AVG)
DMR, Monitor Only - Overdue
pH
0% over limit
Discharged 6.3 SU against a permitted limit of 6.5 SU (MINIMUM)
DMR, Limited - Numeric Violation
April 30, 2025
Flow, in conduit or thru treatment plant
0% over limit
Discharged 0 MGD against a permitted limit of 0 MGD (MO AVG)
DMR, Monitor Only - Overdue
March 31, 2025
Flow, in conduit or thru treatment plant
0% over limit
Discharged 0 MGD against a permitted limit of 0 MGD (MO AVG)
DMR, Monitor Only - Overdue
February 28, 2025
Flow, in conduit or thru treatment plant
0% over limit
Discharged 0 MGD against a permitted limit of 0 MGD (MO AVG)
DMR, Monitor Only - Overdue
January 31, 2025
Flow, in conduit or thru treatment plant
0% over limit
Discharged 0 MGD against a permitted limit of 0 MGD (MO AVG)
DMR, Monitor Only - Overdue
December 31, 2024
Flow, in conduit or thru treatment plant
0% over limit
Discharged 0 MGD against a permitted limit of 0 MGD (MO AVG)
DMR, Monitor Only - Overdue
November 30, 2024
Flow, in conduit or thru treatment plant
0% over limit
Discharged 0 MGD against a permitted limit of 0 MGD (MO AVG)
DMR, Monitor Only - Overdue
Mercury, total recoverable
0% over limit
Discharged 0 mg/L against a permitted limit of 0.000007 mg/L (MO AVG)
DMR, Limited - Overdue
Sulfide, total [as S]
0% over limit
Discharged 0 kg/d against a permitted limit of 0 kg/d (DAILY MX)
DMR, Monitor Only - Overdue
Cyanide, total [as CN]
0% over limit
Discharged 0 mg/L against a permitted limit of 0.015 mg/L (DAILY MX)
DMR, Limited - Overdue
Mercury, total recoverable
0% over limit
Discharged 0 kg/d against a permitted limit of 0.001 kg/d (DAILY MX)
DMR, Limited - Overdue
Hydrogen sulfide
0% over limit
Discharged 0 mg/L against a permitted limit of 0.002 mg/L (MO AVG)
DMR, Limited - Overdue
Sulfide, total [as S]
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (MO AVG)
DMR, Monitor Only - Overdue
Selenium, total recoverable
0% over limit
Discharged 0 mg/L against a permitted limit of 0.002 mg/L (MO AVG)
DMR, Limited - Overdue
Hydrogen sulfide
0% over limit
Discharged 0 kg/d against a permitted limit of 0.09 kg/d (MO AVG)
DMR, Limited - Overdue
Cyanide, total [as CN]
0% over limit
Discharged 0 mg/L against a permitted limit of 0.0081 mg/L (MO AVG)
DMR, Limited - Overdue
Selenium, total recoverable
0% over limit
Discharged 0 kg/d against a permitted limit of 0.09 kg/d (MO AVG)
DMR, Limited - Overdue
Sulfide, total [as S]
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (DAILY MX)
DMR, Monitor Only - Overdue
Hydrogen sulfide
0% over limit
Discharged 0 mg/L against a permitted limit of 0.003 mg/L (DAILY MX)
DMR, Limited - Overdue
Selenium, total recoverable
0% over limit
Discharged 0 mg/L against a permitted limit of 0.003 mg/L (DAILY MX)
DMR, Limited - Overdue
Selenium, total recoverable
0% over limit
Discharged 0 kg/d against a permitted limit of 0.20000001 kg/d (DAILY MX)
DMR, Limited - Overdue
Sulfide, total [as S]
0% over limit
Discharged 0 kg/d against a permitted limit of 0 kg/d (MO AVG)
DMR, Monitor Only - Overdue
Mercury, total recoverable
0% over limit
Discharged 0 mg/L against a permitted limit of 0.00002 mg/L (DAILY MX)
DMR, Limited - Overdue
Cyanide, total [as CN]
0% over limit
Discharged 0 kg/d against a permitted limit of 0.43000002 kg/d (MO AVG)
DMR, Limited - Overdue
Mercury, total recoverable
0% over limit
Discharged 0 kg/d against a permitted limit of 0.0004 kg/d (MO AVG)
DMR, Limited - Overdue
Hydrogen sulfide
0% over limit
Discharged 0 kg/d against a permitted limit of 0.20000001 kg/d (DAILY MX)
DMR, Limited - Overdue
Cyanide, total [as CN]
0% over limit
Discharged 0 kg/d against a permitted limit of 0.82000004 kg/d (DAILY MX)
DMR, Limited - Overdue
October 31, 2024
Flow, in conduit or thru treatment plant
0% over limit
Discharged 0 MGD against a permitted limit of 0 MGD (MO AVG)
DMR, Monitor Only - Overdue
First flagged
April 14, 2026 (3 months ago)
Last confirmed
July 13, 2026 (23 days ago)