Violation ID |
Occurrence Date |
Violation Type |
Violation Description(-) |
Violation Status |
Priority |
Source |
Facility Name |
Violated Reg. Meas. ID |
Violated Reg. Meas. Order No. |
Linked to Enf. |
1106975 |
07/26/2022 |
CAT2 |
Chlorine, Total Residual Instantaneous Maximum limit is 0.0 mg/L and reported value was .85 mg/L at EFF-001. |
Violation |
N |
eSMR |
San Mateo WWTP |
421205 |
R2-2018-0016 |
Y |
1106977 |
07/02/2022 |
CAT1 |
Carbonaceous Biochemical Oxygen Demand (CBOD) (5-day @ 20 Deg. C) Weekly Average limit is 25 mg/L and reported value was 27.4 mg/L at EFF-001. |
Violation |
N |
eSMR |
San Mateo WWTP |
421205 |
R2-2018-0016 |
Y |
1121955 |
10/27/2023 |
CAT2 |
Chlorine, Total Residual Instantaneous Maximum limit is 0 mg/L and reported value was 0.055 mg/L at EFF-001. |
Violation |
N |
eSMR |
San Mateo WWTP |
421205 |
R2-2018-0016 |
N |
1121954 |
10/12/2023 |
CAT2 |
Chlorine, Total Residual Instantaneous Maximum limit is 0 mg/L and reported value was 0.25 mg/L at EFF-001. |
Violation |
N |
eSMR |
San Mateo WWTP |
421205 |
R2-2018-0016 |
N |
1096360 |
10/25/2021 |
Order Conditions |
The City of San Mateo experienced a major storm event On October 24, 2021. On Oct 25, 2021, treated final effluent discharged onto East 3rd Avenue and into a City of Foster City storm drain. Per Foster City staff, this storm drain travels south and discharges into the San Francisco Bay via the Foster City Lagoon. |
Violation |
N |
eSMR |
San Mateo WWTP |
421205 |
R2-2018-0016 |
N |
1122963 |
11/26/2023 |
CAT2 |
Chlorine, Total Residual Instantaneous Maximum limit is 0 mg/L and reported value was 0.56 mg/L at EFF-001. |
Violation |
N |
eSMR |
San Mateo WWTP |
421205 |
R2-2018-0016 |
N |
1124191 |
01/23/2024 |
Deficient Monitoring |
The Plant performed a titration but failed to properly record the data during the 0500 hour. |
Violation |
N |
eSMR |
San Mateo WWTP |
454700 |
R2-2023-0017 |
N |
1124190 |
01/15/2024 |
Deficient Monitoring |
failure to perform the required hourly titration during the 0600 hour. |
Violation |
N |
eSMR |
San Mateo WWTP |
454700 |
R2-2023-0017 |
N |
1092275 |
06/18/2021 |
Order Conditions |
The unauthorized discharge event took place on Friday, June 18, 2021 at 0600, 0800, and 0945, at the City of San Mateo WWTP. Approximately 3,056 gallons of raw wastewater from a Foster City force main bypass, overflowed out of a manhole onto Detroit Drive. The event was reported to the Case Worker by using the formal Five-Day Report on June 22, 2021. Please see attachment 2 in the June eSMR for detail. |
Violation |
N |
eSMR |
San Mateo WWTP |
421205 |
R2-2018-0016 |
N |
1122962 |
11/01/2023 |
CAT2 |
Chlorine, Total Residual Instantaneous Maximum limit is 0 mg/L and reported value was 0.1 mg/L at EFF-001. |
Violation |
N |
eSMR |
San Mateo WWTP |
421205 |
R2-2018-0016 |
N |
1098821 |
12/23/2021 |
Order Conditions |
December 23, 2021, an unauthorized discharge occurred due to very high effluent flows which dislodged a temporary plug in a corroded automatic relief valve nozzle at the ARV#6 vault. The initial estimated unauthorized discharged quantity of 40-45,000 gallons reported to all required parties. The final discharge quantity of 158,400 gallons was reported in the 5-day report. The discharge took place over an 8-hour period. During this 8-hour period the discharge occurred at effluent flows above 37MGD for 5.5-hours. |
Violation |
N |
eSMR |
San Mateo WWTP |
421205 |
R2-2018-0016 |
N |
1098820 |
12/16/2021 |
Order Conditions |
The week of December 13, 2021, the Monday through Friday average effluent flow was 25.59 MGD with effluent flow peaks up to 50 MGD (normal average dry weather flows of 9 MGD). It is assumed but has not been confirmed that utilization of the final effluent storm pumps to handle the increased flows resulted in a discharge from an unknown location on the outfall pipeline between the final ARV#6 and the bay discharge. On December 16, 2021 water lightly bubbled up out of the soil near the ARV#6 vault into a curbed planter box and then onto a dirt utility road. An estimated 300 gallons was reported to all required parties. |
Violation |
N |
eSMR |
San Mateo WWTP |
421205 |
R2-2018-0016 |
N |
1125037 |
02/02/2024 |
CAT2 |
Chlorine, Total Residual 1-Hour Average (Mean) limit is 0.34 mg/L and reported value was 0.55 mg/L at EFF-001. |
Violation |
N |
eSMR |
San Mateo WWTP |
454700 |
R2-2023-0017 |
Y |
1106976 |
07/02/2022 |
CAT1 |
Total Suspended Solids (TSS) Weekly Average (Mean) limit is 30 mg/L and reported value was 41.5 mg/L at EFF-001. |
Violation |
N |
eSMR |
San Mateo WWTP |
421205 |
R2-2018-0016 |
Y |
1106470 |
06/30/2022 |
CAT1 |
Carbonaceous Biochemical Oxygen Demand (CBOD) (5-day @ 20 Deg. C) Monthly Average (Mean) limit is 15 mg/L and reported value was 15.5 mg/L at EFF-001. |
Violation |
N |
eSMR |
San Mateo WWTP |
421205 |
R2-2018-0016 |
Y |
1121048 |
09/13/2023 |
CAT2 |
Chlorine, Total Residual Instantaneous Maximum limit is 0.0 mg/L and reported value was 1.35 mg/L at EFF-001. |
Violation |
N |
eSMR |
San Mateo WWTP |
421205 |
R2-2018-0016 |
Y |
1118641 |
06/27/2023 |
CAT2 |
Chlorine, Total Residual Instantaneous Maximum limit is 0.0 mg/L and reported value was 0.1 mg/L at EFF-001. |
Violation |
N |
eSMR |
San Mateo WWTP |
421205 |
R2-2018-0016 |
Y |
1133796 |
01/23/2024 |
Sanitary Sewer Overflow/Spill/ |
Type: Category 1 Spill; Fats, Oil and Grease (FOG) caused 5300 gallons of sewage to spill from Manhole at 1630 Bayridge Way to Unpaved Surface |
Violation |
None |
SSO |
San Mateo CIty CS |
300189 |
2022-0103-DWQ |
N |
1139833 |
01/30/2025 |
Sanitary Sewer Overflow/Spill/ |
Type: Category 1 Spill; Other (specify below),Damage by Others Not Related to Collection System Construction/Maintenance caused 707 gallons of sewage to spill from Other (specify below) at Mariners Island 3 Force Main to Drainage Conveyance System that discharges to surface water |
Violation |
None |
SSO |
San Mateo CIty CS |
300189 |
2022-0103-DWQ |
N |
1140508 |
02/13/2025 |
Sanitary Sewer Overflow/Spill/ |
Type: Category 1 Spill; Flow Exceeded Capacity (Separate Collection System Only) caused 270000 gallons of sewage to spill from Manhole at Saratoga UFES to Surface Water |
Violation |
None |
SSO |
San Mateo CIty CS |
300189 |
2022-0103-DWQ |
N |
1133795 |
01/22/2024 |
Sanitary Sewer Overflow/Spill/ |
Type: Category 1 Spill; Debris-wipes/Non-disposables, Root Intrusion caused 1850 gallons of sewage to spill from Manhole at Bromfield and Chester way to Surface Water |
Violation |
None |
SSO |
San Mateo CIty CS |
300189 |
2022-0103-DWQ |
N |
1138589 |
12/31/2024 |
Sanitary Sewer Overflow/Spill/ |
Type: Category 1 Spill; Fats, Oil and Grease (FOG) caused 3200 gallons of sewage to spill from Manhole,Gravity Mainline at S Norfolk st. and Lago st. to Drainage Conveyance System that discharges to surface water |
Violation |
None |
SSO |
San Mateo CIty CS |
300189 |
2022-0103-DWQ |
N |
1142177 |
02/15/2025 |
Sanitary Sewer Overflow/Spill/ |
Type: Category 1 Spill; Other (specify below) caused 613500 gallons of sewage to spill from Manhole at 3905 Kingridge Drive to Surface Water |
Violation |
None |
SSO |
San Mateo CIty CS |
300189 |
2022-0103-DWQ |
N |
1133794 |
12/20/2023 |
Sanitary Sewer Overflow/Spill/ |
Type: Category 1 Spill; Other (specify below) caused 75600 gallons of sewage to spill from Gravity Mainline, Lateral Clean Out (Private), Manhole at Hillsdale and Saratoga to Drainage Conveyance System |
Violation |
None |
SSO |
San Mateo CIty CS |
300189 |
2022-0103-DWQ |
N |
1138282 |
12/14/2024 |
Sanitary Sewer Overflow/Spill/ |
Type: Category 1 Spill; Other (specify below) caused 5400 gallons of sewage to spill from Manhole at Saratoga between Delaware and UFES to Street/Curb and Gutter (2 3) |
Violation |
None |
SSO |
San Mateo CIty CS |
300189 |
2022-0103-DWQ |
N |
1141079 |
02/15/2025 |
Sanitary Sewer Overflow/Spill/ |
Type: Category 1 Spill; Other (specify below) caused 684000 gallons of sewage to spill from Manhole at 3905 Kingridge Drive to Surface Water |
Violation |
None |
SSO |
San Mateo CIty CS |
300189 |
2022-0103-DWQ |
N |
1138285 |
12/14/2024 |
Sanitary Sewer Overflow/Spill/ |
Type: Category 1 Spill; Other (specify below) caused 19500 gallons of sewage to spill from Manhole at Saratoga between Delaware and UFES to Street/Curb and Gutter (2 3) |
Violation |
None |
SSO |
San Mateo CIty CS |
300189 |
2022-0103-DWQ |
N |
1133797 |
06/24/2024 |
Sanitary Sewer Overflow/Spill/ |
Type: Category 1 Spill; Root Intrusion caused 1200 gallons of sewage to spill from Manhole at 931 Viewridge to Surface Water, Unpaved Surface |
Violation |
None |
SSO |
San Mateo CIty CS |
300189 |
2022-0103-DWQ |
N |
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