CUPERTINO QUARRY
NPDES ID: CA0030236
X — SNC: Effluent violation (non-monthly average limit)
The facility discharged more of a pollutant than its permit allows, measured over a period other than a monthly average.
This quarter: 1 compliance schedule violation.
Violations
December 31, 2025
Chromium, hexavalent [as Cr]
150% over limit
Discharged 0.014 mg/L against a permitted limit of 0.0056 mg/L (MO AVG)
DMR, Limited - Numeric Violation
September 30, 2025
Chromium, hexavalent [as Cr]
150% over limit
Discharged 0.04 mg/L against a permitted limit of 0.016 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (DAILY MX)
DMR, Monitor Only - Overdue
Chromium, hexavalent [as Cr]
614% over limit
Discharged 0.04 mg/L against a permitted limit of 0.0056 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Chromium, hexavalent dissolved [as Cr]
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (DAILY MX)
DMR, Monitor Only - Overdue
Chromium, trivalent dissolved, as Cr
0% over limit
Discharged 0 mg/L against a permitted limit of 0 mg/L (DAILY MX)
DMR, Monitor Only - Overdue
February 28, 2025
Chromium, hexavalent [as Cr]
132% over limit
Discharged 0.013 mg/L against a permitted limit of 0.0056 mg/L (MO AVG)
DMR, Limited - Numeric Violation
January 31, 2025
Chromium, hexavalent [as Cr]
150% over limit
Discharged 0.014 mg/L against a permitted limit of 0.0056 mg/L (MO AVG)
DMR, Limited - Numeric Violation
% Survival Static Renewal 96Hr Acute Pimephales promelas
0% over limit
Discharged 0 % against a permitted limit of 70 % (MINIMUM)
DMR, Limited - Overdue
December 31, 2024
% Survival Static Renewal 96Hr Acute Pimephales promelas
7% over limit
Discharged 65 % against a permitted limit of 70 % (MINIMUM)
DMR, Limited - Numeric Violation
Chromium, hexavalent [as Cr]
614% over limit
Discharged 0.04 mg/L against a permitted limit of 0.0056 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Chromium, hexavalent [as Cr]
150% over limit
Discharged 0.04 mg/L against a permitted limit of 0.016 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
% Survival Static Renewal 96Hr Acute Pimephales promelas
7% over limit
Discharged 65 % against a permitted limit of 70 % (MINIMUM)
DMR, Limited - Numeric Violation
Chromium, hexavalent [as Cr]
150% over limit
Discharged 0.04 mg/L against a permitted limit of 0.016 mg/L (DAILY MX)
DMR, Limited - Numeric Violation
Chromium, hexavalent [as Cr]
614% over limit
Discharged 0.04 mg/L against a permitted limit of 0.0056 mg/L (MO AVG)
DMR, Limited - Numeric Violation
November 30, 2024
%Surv Static Renewal 96Hr Oncorhynchus mykiss
0% over limit
Discharged 0 % against a permitted limit of 70 % (MINIMUM)
DMR, Limited - Overdue
Chromium, hexavalent [as Cr]
36% over limit
Discharged 0.0076 mg/L against a permitted limit of 0.0056 mg/L (MO AVG)
DMR, Limited - Numeric Violation
% Survival Static Renewal 96Hr Acute Pimephales promelas
0% over limit
Discharged 0 % against a permitted limit of 70 % (MINIMUM)
DMR, Limited - Overdue
First flagged
April 14, 2026 (3 months ago)
Last confirmed
July 13, 2026 (23 days ago)