| Violation ID |
Occurred Date |
Violation Type |
(-) Violation Description |
Corrective Action |
Status |
Classification |
Source |
| 1147838 |
08/31/2025 |
CTOX |
Chronic Toxicity-C.dubia-Reproduction Monthly Median limit is 0 Pass/Fail (Pass = 0, Fail = 1) and reported value was 1 Pass/Fail (Pass = 0, Fail = 1) at M-001A. |
Operations staff have performed bi-weekly lateral flushing's, replaced composite sampler tubing, cleaned composite sampler carboy, and disinfected the M-001A composite sampler. These actions have shown to mitigate against contamination as the M-001A toxicity has passed during the month of September 2025. |
Violation |
U |
eSMR |
| 1145336 |
06/30/2025 |
CTOX |
Chronic Toxicity-C.dubia-Reproduction Monthly Median limit is 0 Pass/Fail (Pass = 0, Fail = 1) and reported value was 1 Pass/Fail (Pass = 0, Fail = 1) at M-001A. |
Operations staff flushed the laterals, disinfected the composite sampler (including the carboy), replaced the sampler tubing, and rinsed the sample bottles prior to collecting samples. The IEUA Toxicity Task Force will continue to evaluate the toxicity test results closely on a continuous basis. |
Violation |
U |
eSMR |
| 1144239 |
04/30/2025 |
CTOX |
Chronic Toxicity-C.dubia-Reproduction Monthly Median limit is 0 Pass/Fail (Pass = 0, Fail = 1) and reported value was 1 Pass/Fail (Pass = 0, Fail = 1) at M-001A. |
In previous investigations, it was speculated that low flow (<2 mgd) at DP-001 could have caused disinfection byproduct formation due to additional contact time of organic matter and sodium hypochlorite in the pipeline. DP-001 is primarily comprised of RP-5 effluent and discharges of RP-5 effluent at DP-003 continues to pass chronic toxicity for reproduction during the same time that DP-001 has been failing. Additional flushing of the recycled water distribution system and laterals will be performed prior to future testing. IEUA will continue to evaluate the toxicity test results closely for the next few months. |
Violation |
U |
eSMR |
| 1144246 |
04/30/2025 |
CTOX |
Chronic Toxicity-C.dubia-Reproduction Monthly Median limit is 0 Pass/Fail (Pass = 0, Fail = 1) and reported value was 1 Pass/Fail (Pass = 0, Fail = 1) at M-003. |
Operations staff will initiate dechlorination zone cleaning by flushing, draining, bleaching, and scrubbing the entire structure prior to future testing. Operations will ensure proper sampling techniques. Due to the possibility of bad batches of sample bottles, sample bottles will be triple rinsed to ensure there are no contaminants present. Construction of a permanent cover over the dechlorination zone commenced construction. Completion of the cover is anticipated over the next couple months with the intent that the cover will aid in mitigating any potential algae buildup in the dechlorination zone. IEUA Laboratory will begin the TIE to pinpoint the specific causes of toxicity. The IEUA Toxicity Task Force will continue to evaluate the toxicity test results closely for the next few months while working to eliminate the toxicity issue. |
Violation |
U |
eSMR |
| 1144243 |
03/31/2025 |
CTOX |
Chronic Toxicity-C.dubia-Reproduction Monthly Median limit is 0 Pass/Fail (Pass = 0, Fail = 1) and reported value was 1 Pass/Fail (Pass = 0, Fail = 1) at M-003. |
Operations staff will initiate dechlorination zone cleaning by flushing, draining, bleaching, and scrubbing the entire structure prior to future testing. Operations will ensure proper sampling techniques. Due to the possibility of bad batches of sample bottles, sample bottles will be triple rinsed to ensure there are no contaminants present. Construction of a permanent cover over the dechlorination zone commenced construction. Completion of the cover is anticipated over the next couple months with the intent that the cover will aid in mitigating any potential algae buildup in the dechlorination zone. IEUA Laboratory will begin the TIE to pinpoint the specific causes of toxicity. The IEUA Toxicity Task Force will continue to evaluate the toxicity test results closely for the next few months while working to eliminate the toxicity issue. |
Violation |
U |
eSMR |
| 1144237 |
02/28/2025 |
CTOX |
Chronic Toxicity-C.dubia-Reproduction Monthly Median limit is 0 Pass/Fail (Pass = 0, Fail = 1) and reported value was 1 Pass/Fail (Pass = 0, Fail = 1) at M-003. |
Please see "Chino Creek (M-003) IITRE (February 2024)" document in the February 2024 NPDES Report. Prado Lake DP 001 discharge is RP-5 Effluent. This monitoring location (M-001A) has been consistently passing the toxicity testing since September 2023. Routine recycled water distribution system flushing at key locations was implemented for DP 001 and reproduction toxicity at this site went away. The only significant differences between M-001A and M-003 are the dechlorination process and the distance traveled prior to discharge. In early March 2024, the RP-5 dechlorination basin was taken offline two days in a row for several hours to initiate the cleaning of walls and facilitate the passage of chlorine residual, which aids in algae removal. During the cleaning process, the water level rose sufficiently to enable a passive overflow into the Emergency Overflow Basin, effectively clearing out algae and debris from the dechlorination basin. At the time of reporting, IEUA is still interpreting the test results from the recent toxicity testing by the contract labs. |
Violation |
U |
eSMR |
| 1144241 |
01/31/2025 |
CTOX |
Chronic Toxicity-C.dubia-Reproduction Monthly Median limit is 0 Pass/Fail (Pass = 0, Fail = 1) and reported value was 1 Pass/Fail (Pass = 0, Fail = 1) at M-001A. |
In previous investigations, it was speculated that low flow (<2 mgd) at DP-001 could have caused disinfection byproduct formation due to additional contact time of organic matter and sodium hypochlorite in the pipeline. DP-001 is primarily comprised of RP-5 effluent and discharges of RP-5 effluent at DP-003 continues to pass chronic toxicity for reproduction during the same time that DP-001 has been failing. Additional flushing of the recycled water distribution system and laterals will be performed prior to future testing. IEUA will continue to evaluate the toxicity test results closely for the next few months. |
Violation |
U |
eSMR |
| 1138484 |
11/22/2024 |
Surface Water |
On November 22, 2024, the Chino Creek temperature was 28.5 degrees Celsius above the receiving water limitation of 26 degrees Celsius. The discharged temperature reported value was 27.1 degrees Celsius at RP-5 effluent. |
Due to the lack of Chino Creek upstream and CCWRF effluent data, it is difficult to conclude that the RP-5 effluent was not the cause of the exceedances. However, the Chino area had been experiencing warm weather in the month of November and the field testing took place in the afternoon. The higher ambient temperatures and the low flow in the concrete-lined portion of the channel could have caused the higher temperatures at the downstream creek location, R-003D.
1) All field testing of the sites listed in the above table will be conducted on the same day and approximately at the same time. This will provide a better data set to determine if effluent temperature is the cause of an exceedance and to know the background temperature upstream of the discharge points.
2) A work order has been entered to add continuous monitoring for the RP-5 and CCWRF effluent temperatures. This will align with how Regional Plant No. 1 is currently monitoring effluent temperature.
3) The Operations staff will notify Compliance staff when temperature exceedances occur. In addition to conducting periodic training, an electronic solution will need to be implemented to flag an exceedance once it is entered into the data logger.
|
Violation |
U |
eSMR |
| 1138483 |
11/13/2024 |
Surface Water |
On November 13, 2024, the Chino Creek temperature was 28.4 degrees Celsius above the receiving water limitation of 26 degrees Celsius. The discharged temperature reported value was 27.8 degrees Celsius at RP-5 effluent. |
Due to the lack of Chino Creek upstream and CCWRF effluent data, it is difficult to conclude that the RP-5 effluent was not the cause of the exceedances. However, the Chino area had been experiencing warm weather in the month of November and the field testing took place in the afternoon. The higher ambient temperatures and the low flow in the concrete-lined portion of the channel could have caused the higher temperatures at the downstream creek location, R-003D.
1) All field testing of the sites listed in the above table will be conducted on the same day and approximately at the same time. This will provide a better data set to determine if effluent temperature is the cause of an exceedance and to know the background temperature upstream of the discharge points.
2) A work order has been entered to add continuous monitoring for the RP-5 and CCWRF effluent temperatures. This will align with how Regional Plant No. 1 is currently monitoring effluent temperature.
3) The Operations staff will notify Compliance staff when temperature exceedances occur. In addition to conducting periodic training, an electronic solution will need to be implemented to flag an exceedance once it is entered into the data logger.
|
Violation |
U |
eSMR |
| 1144240 |
05/31/2024 |
CTOX |
Chronic Toxicity-C.dubia-Reproduction Monthly Median limit is 0 Pass/Fail (Pass = 0, Fail = 1) and reported value was 1 Pass/Fail (Pass = 0, Fail = 1) at M-001A. |
Please see "Prado Lake (001A) IITRE (May 2024)" document in the May 2024 NPDES Report.In previous investigations, it was speculated that low flow (<2 mgd) at DP-001 could have caused disinfection byproduct formation due to additional contact time of organic matter and sodium hypochlorite in the pipeline. DP-001 is primarily comprised of RP-5 effluent and discharges of RP-5 effluent at DP-003 continues to pass chronic toxicity for reproduction during the same time that DP-001 has been failing. Additional flushing of the recycled water distribution system and laterals will be performed prior to future testing. IEUA will continue to evaluate the toxicity test results closely for the next few months. Update: Toxicity was no longer found in June 2024 at M-001A. |
Violation |
U |
eSMR |
| 1144238 |
03/31/2024 |
CTOX |
Chronic Toxicity-C.dubia-Reproduction Monthly Median limit is 0 Pass/Fail (Pass = 0, Fail = 1) and reported value was 1 Pass/Fail (Pass = 0, Fail = 1) at M-003. |
Please see "Chino Creek (M-003) IITRE (March 2024)" document in the March 2024 NPDES Report. Prado Lake DP 001 discharge is RP-5 Effluent. This monitoring location (M-001A) has been consistently passing the toxicity testing since September 2023. Routine recycled water distribution system flushing at key locations was implemented for DP 001 and reproduction toxicity at this site went away. The only significant differences between M-001A and M-003 are the dechlorination process and the distance traveled prior to discharge. In early March 2024, the RP-5 dechlorination basin was taken offline two days in a row for several hours to initiate the cleaning of walls and facilitate the passage of chlorine residual, which aids in algae removal. During the cleaning process, the water level rose sufficiently to enable a passive overflow into the Emergency Overflow Basin, effectively clearing out algae and debris from the dechlorination basin. Addition cleaning and flushing has taken place in April 2024. IEUA will continue to evaluate the effectiveness of the cleanings based on toxicity results in the coming months. Update: Toxicity was no longer found in April 2024 at M-003. |
Violation |
U |
eSMR |
| 1144236 |
01/31/2024 |
CTOX |
Chronic Toxicity-C.dubia-Reproduction Monthly Median limit is 0 Pass/Fail (Pass = 0, Fail = 1) and reported value was 1 Pass/Fail (Pass = 0, Fail = 1) at M-003. |
Please see "Chino Creek (M-003) IITRE (January 2024)" document in the January 2024 NPDES Report. Prado Lake DP 001 discharge is RP-5 Effluent. This monitoring location (M-001A) has been consistently passing the toxicity testing since September 2023. Routine recycled water distribution system flushing at key locations was implemented for DP 001 and reproduction toxicity at this site went away. The only significant differences between M-001A and M-003 are the dechlorination process and the distance traveled prior to discharge. Compliance staff has recommended the dechlorination basins at RP-5 be cleaned to eliminate the formation of disinfection byproducts or other compounds from the interaction of sodium hypochlorite with solid i the basin. Further investigation is necessary. |
Violation |
U |
eSMR |
| 1121049 |
07/07/2023 |
CAT2 |
Chlorine, Total Residual Instantaneous Maximum limit is 0.1 mg/L and reported value was 3.3 mg/L at M-001A. |
The following items are completed action items to help mitigate potential future incidents of this nature.
1) MCC No.1 main circuit breaker replaced.
2) Emergency onsite generator test completed after MCC No. 1 main circuit breaker replacement. Emergency onsite generator turned on seamlessly and provided the necessary power to the SBS pumps when the main utility power was disconnected. |
Violation |
U |
eSMR |
| 1115441 |
04/02/2023 |
LREP |
Annual SMR ( SUMRPT ) report for 2022 (2553933) was due on 01-APR-23 |
|
Violation |
B |
Report |
| 1115500 |
04/02/2023 |
LREP |
Annual SMR ( SUMRPT ) report for 2022 (2711194) was due on 01-APR-23 |
|
Violation |
B |
Report |
| 1115059 |
12/31/2022 |
DMON |
M-003
Annual Perchlorate - IEUA missed analysis |
Collect additional sample in addition to the annual sample in 2023. |
Violation |
U |
eSMR |
| 1115061 |
12/31/2022 |
DMON |
M-INF 3C (RP-2 Recycled Flow)
Annual TCDD (full list) - IEUA missed analysis |
Collect additional sample in addition to the annual sample in 2023. |
Violation |
U |
eSMR |
| 1109293 |
10/01/2022 |
LREP |
Annual SMR ( PRETRPT ) report for 2021 (2416108) was due on 30-SEP-22 |
|
Violation |
B |
Report |
| 1103432 |
08/31/2021 |
DMON |
Toxicity data was not reported for 003-A for August 2021. Discharger used NODI P (for lab error) in DMRs triggering a violation. No data reported in eSMR or uploaded in attachments to verify/validate. |
|
Violation |
B |
Report |
|
Report displays most recent five years of violations. Refer to the Interactive Violation Report for more data.
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