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California · California (CIWQS)

San Mateo City

D
Frequently reaches water
Reported events
514
Total volume
12.6M gal
Reached waterways
208 (40%)
Reporting since
2007

What caused the overflows

Root Intrusion
176
Grease / FOG
122
Other / Unknown
74
Rainfall / Flooding
60
Equipment Failure
44
Capacity Issue
38

Reported overflow events (showing 200 of 514)

DateVolumeCauseReached waterReceiving water
May 15, 2026240 galRoot Intrusion——
Apr 21, 2026600 galEquipment FailureYesSan Mateo Creek
Apr 2, 2026150 galEquipment Failure——
Mar 30, 202655 galGrease / FOGYesSan francisco bay
Feb 18, 2026225 galRoot IntrusionYesLeslie creek
Feb 14, 20262K galOther / UnknownYesSan francisco bay
Feb 10, 20261K galGrease / FOGYesbay water system
Feb 9, 20267K galGrease / FOGYesCrystal Springs Creek and SF Bay
Feb 6, 2026960 galGrease / FOGYesSan francisco bay
Jan 4, 2026975 galRainfall / FloodingYesLeslie creek
Jan 3, 2026449K galGrease / FOG——
Dec 2, 2025200 galCapacity IssueYesSan francisco bay
Nov 25, 202527K galGrease / FOGYesLaurel Creek
Nov 23, 2025100 galEquipment Failure——
Aug 27, 20254K galRoot IntrusionYesLaurel creek
Aug 25, 2025180 galGrease / FOG——
Aug 13, 2025165 galGrease / FOGYesLaurel Creek
Apr 3, 2025200 galRoot Intrusion——
Feb 15, 2025684K galOther / UnknownYesunnamed waterway leading to laurel creek
Feb 15, 2025614K galOther / UnknownYesunnamed waterway leading to laurel creek
Feb 13, 2025270K galCapacity IssueYesBorel Creek
Feb 12, 2025920 galGrease / FOG——
Jan 30, 2025707 galEquipment FailureYesMarina Lagoon
Dec 31, 20243K galGrease / FOGYesMarina lagoon
Dec 14, 202420K galOther / UnknownYesBorel Creek
Dec 14, 20245K galOther / UnknownYesBorel Creek
Jul 18, 2024200 galOther / Unknown——
Jun 24, 20241K galRoot IntrusionYesunnamed waterway leading to laurel creek
Apr 16, 20247K galGrease / FOGYesSan francisco bay
Jan 23, 20245K galGrease / FOGYesLaurel Creek
Jan 22, 20242K galRoot IntrusionYescherry canyon creek
Dec 20, 202376K galOther / UnknownYesBorel Creek
Jun 7, 202310 galRoot Intrusion—Unpaved surface
Apr 13, 202322 galRoot Intrusion—Street/Curb and Gutter
Apr 10, 2023140 galRoot Intrusion—Street/Curb and Gutter
Mar 21, 2023820K galOther / UnknownYesDrainage Channel
Mar 12, 2023108K galCapacity IssueYesDrainage Channel
Feb 21, 2023105 galGrease / FOG—Separate Storm Drain;Street/Curb and Gutter
Jan 14, 2023203K galCapacity IssueYesDrainage Channel
Jan 9, 2023272K galCapacity IssueYesDrainage Channel
Jan 9, 2023272K galCapacity IssueYesDrainage Channel
Jan 4, 2023460K galRainfall / FloodingYesDrainage Channel
Dec 31, 2022495K galRainfall / FloodingYesDrainage Channel
Dec 27, 20229K galRainfall / FloodingYesDrainage Channel;Other (specify below)
Dec 16, 202260 galRoot Intrusion—Street/Curb and Gutter
Dec 16, 202255 galRoot Intrusion—Unpaved surface
Nov 18, 2022175 galRoot Intrusion—Unpaved surface
Oct 25, 20222K galOther / UnknownYesPaved Surface;Separate Storm Drain;Street/Curb and Gutter
Jul 16, 2022250 galRoot Intrusion—Separate Storm Drain;Street/Curb and Gutter
Dec 23, 2021360 galRainfall / FloodingYesSurface Water
Dec 13, 202123K galCapacity IssueYesSeparate Storm Drain
Nov 1, 2021129 galRoot Intrusion—Separate Storm Drain;Street/Curb and Gutter
Oct 24, 2021340K galRainfall / FloodingYesDrainage Channel
Oct 17, 20212K galOther / Unknown—Separate Storm Drain;Street/Curb and Gutter
Aug 5, 2021375 galOther / Unknown—Unpaved surface
Jul 9, 202112 galGrease / FOG—Street/Curb and Gutter
Jun 9, 20212K galGrease / FOGYesSeparate Storm Drain;Surface Water
May 1, 2021336 galRoot Intrusion—Other (specify below)
Apr 16, 2021545 galEquipment Failure—Separate Storm Drain;Street/Curb and Gutter
Apr 6, 20215 galGrease / FOG—Separate Storm Drain
Mar 29, 202168 galRoot Intrusion—Paved Surface;Unpaved surface
Mar 1, 2021158 galGrease / FOGYesSeparate Storm Drain;Surface Water
Feb 17, 2021248 galRoot Intrusion—Unpaved surface
Feb 5, 20215 galGrease / FOGYesSurface Water
Feb 3, 2021110 galGrease / FOG—Separate Storm Drain;Street/Curb and Gutter
Jan 24, 2021150 galGrease / FOG—Building or Structure
Jan 23, 20211K galRoot Intrusion—Unpaved surface
Jan 21, 202156 galOther / Unknown—Separate Storm Drain;Street/Curb and Gutter
Jan 19, 2021180 galGrease / FOG—Street/Curb and Gutter
Jan 19, 202196 galRoot Intrusion—Unpaved surface
Jan 19, 2021350 galRoot IntrusionYesSurface Water
Jan 19, 2021104 galRoot Intrusion—Unpaved surface
Jan 11, 202110 galEquipment Failure—Street/Curb and Gutter
Jan 8, 202113 galGrease / FOGYesSeparate Storm Drain
Dec 24, 2020565 galRoot Intrusion—Building or Structure;Paved Surface
Nov 20, 2020598 galRoot Intrusion—Paved Surface
Nov 20, 202074 galRoot Intrusion—Paved Surface;Street/Curb and Gutter
Oct 15, 20208 galRoot Intrusion—Building or Structure;Unpaved surface
Sep 15, 202036 galRoot Intrusion—Paved Surface
Sep 15, 202022 galEquipment Failure—Unpaved surface
Sep 5, 202010K galGrease / FOGYesSurface Water
Jul 21, 202058 galRoot IntrusionYesSeparate Storm Drain;Street/Curb and Gutter
Jul 13, 202020 galRoot Intrusion—Street/Curb and Gutter
Jun 5, 2020200 galRoot Intrusion—Separate Storm Drain;Street/Curb and Gutter
May 9, 2020139K galEquipment FailureYesDrainage Channel;Separate Storm Drain;Surface Water
Apr 24, 2020810 galOther / Unknown—Separate Storm Drain
Apr 7, 2020101 galGrease / FOGYesSeparate Storm Drain
Apr 3, 202018 galGrease / FOG—Street/Curb and Gutter;Unpaved surface
Mar 20, 20203K galRoot Intrusion—Unpaved surface
Mar 4, 202021 galRoot Intrusion—Unpaved surface
Jan 9, 202035 galEquipment Failure—Separate Storm Drain
Nov 17, 2019306 galEquipment Failure—Building or Structure
Nov 7, 2019255 galOther / Unknown—Separate Storm Drain
Oct 24, 20194 galRoot Intrusion—Street/Curb and Gutter
Oct 24, 201959 galOther / Unknown—Street/Curb and Gutter
Oct 24, 20191K galRoot IntrusionYesSurface Water
Oct 23, 2019310 galRoot IntrusionYesSurface Water
Oct 11, 2019149 galEquipment Failure—Separate Storm Drain;Street/Curb and Gutter
Jul 28, 2019535 galRoot Intrusion—Building or Structure;Paved Surface
May 28, 20193K galEquipment FailureYesSeparate Storm Drain;Surface Water
Apr 17, 2019469 galRoot Intrusion—Separate Storm Drain
Apr 16, 2019467 galEquipment Failure—Separate Storm Drain
Mar 21, 20192K galOther / Unknown—Separate Storm Drain;Street/Curb and Gutter
Mar 13, 20191 galGrease / FOG—Paved Surface
Mar 11, 201959 galEquipment Failure—Separate Storm Drain;Street/Curb and Gutter
Mar 6, 2019780 galEquipment Failure—Unpaved surface
Mar 6, 20191K galRoot IntrusionYesSeparate Storm Drain;Surface Water
Feb 22, 201914 galEquipment Failure—Street/Curb and Gutter
Feb 14, 201948K galRainfall / FloodingYesSurface Water
Jan 29, 2019425 galOther / Unknown—Unpaved surface
Jan 19, 201947K galOther / UnknownYesStreet/Curb and Gutter;Surface Water
Jan 17, 2019837 galGrease / FOG—Paved Surface
Jan 16, 201925K galRainfall / FloodingYesSurface Water
Jan 10, 20191K galRoot IntrusionYesSurface Water
Jan 6, 20196K galRainfall / FloodingYesSurface Water
Jan 2, 2019135 galRoot Intrusion—Building or Structure
Dec 15, 20187 galGrease / FOG—Paved Surface
Nov 30, 2018135 galGrease / FOG—Separate Storm Drain
Sep 28, 2018167 galRoot Intrusion—Unpaved surface
Sep 7, 2018255 galRoot Intrusion—Unpaved surface
Jul 21, 20188K galEquipment Failure—Paved Surface
Jun 25, 2018104 galRoot Intrusion—Building or Structure;Paved Surface
Jun 20, 201855 galGrease / FOG—Street/Curb and Gutter
Jun 15, 2018963 galGrease / FOG—Building or Structure
Mar 8, 201818 galEquipment Failure—Unpaved surface
Mar 6, 201857 galEquipment Failure—Separate Storm Drain;Street/Curb and Gutter
Mar 1, 201820 galRoot Intrusion—Separate Storm Drain
Jan 18, 201817 galRoot Intrusion—Separate Storm Drain;Street/Curb and Gutter
Jan 8, 201877K galRainfall / FloodingYesSurface Water
Dec 5, 2017476 galRoot Intrusion—Paved Surface;Separate Storm Drain;Street/Curb and Gutter
Aug 12, 201772 galRoot Intrusion—Separate Storm Drain
May 17, 201725 galRoot Intrusion—Separate Storm Drain
May 2, 201730 galGrease / FOGYesSurface Water
Apr 29, 2017663 galEquipment FailureYesSurface Water
Mar 17, 20172K galRoot Intrusion—Separate Storm Drain
Mar 17, 20172K galRoot IntrusionYesSeparate Storm Drain
Feb 23, 2017222 galGrease / FOG—Separate Storm Drain;Street/Curb and Gutter
Feb 20, 2017183K galRainfall / FloodingYesSurface Water
Feb 9, 20173K galRoot Intrusion—Unpaved surface
Feb 7, 201763K galRainfall / FloodingYesSurface Water
Feb 6, 2017282 galRoot Intrusion—Unpaved surface
Feb 1, 2017171 galRoot Intrusion—Unpaved surface
Jan 20, 201721K galRainfall / FloodingYesSurface Water
Jan 10, 2017259K galRainfall / FloodingYesSurface Water
Dec 28, 2016150 galRoot IntrusionYesDrainage Channel
Nov 14, 20164K galEquipment Failure—Separate Storm Drain;Street/Curb and Gutter
Nov 1, 2016150 galGrease / FOG—Street/Curb and Gutter
Oct 30, 20162 galGrease / FOG—Street/Curb and Gutter
May 1, 2016112 galGrease / FOG—Separate Storm Drain;Street/Curb and Gutter
Apr 20, 2016636 galEquipment Failure—Unpaved surface
Mar 26, 201680 galRoot Intrusion—Separate Storm Drain
Mar 23, 2016900 galEquipment FailureYesSurface Water
Mar 14, 201646 galRoot Intrusion—Street/Curb and Gutter
Mar 13, 201681K galRainfall / FloodingYesSurface Water
Mar 11, 2016101 galGrease / FOG—Unpaved surface
Mar 6, 2016146K galRainfall / FloodingYesDrainage Channel;Surface Water
Mar 5, 2016296K galRainfall / FloodingYesDrainage Channel;Surface Water
Mar 1, 201618 galGrease / FOG—Separate Storm Drain;Street/Curb and Gutter
Feb 24, 201619 galRoot Intrusion—Unpaved surface
Feb 12, 20166 galRoot Intrusion—Building or Structure
Feb 11, 2016149 galOther / Unknown—Paved Surface;Street/Curb and Gutter
Jan 25, 201664 galRoot Intrusion—Paved Surface;Separate Storm Drain;Street/Curb and Gutter
Jan 24, 20163K galRoot Intrusion—Separate Storm Drain;Street/Curb and Gutter
Jan 20, 20162K galGrease / FOGYesBeach;Surface Water
Jan 19, 2016271 galRoot Intrusion—Building or Structure;Unpaved surface
Dec 10, 2015750 galRoot Intrusion—Separate Storm Drain
Dec 9, 2015306 galRoot Intrusion—Paved Surface;Separate Storm Drain;Street/Curb and Gutter
Dec 4, 201523 galEquipment Failure—Paved Surface
Dec 2, 2015324 galGrease / FOG—Paved Surface;Street/Curb and Gutter
Nov 24, 20151K galRoot Intrusion—Building or Structure;Unpaved surface
Nov 23, 20153K galRoot Intrusion—Separate Storm Drain;Street/Curb and Gutter
Oct 19, 2015167 galOther / Unknown—Unpaved surface
Aug 27, 2015525 galOther / Unknown—Separate Storm Drain;Street/Curb and Gutter
Aug 5, 201532 galEquipment Failure—Separate Storm Drain
Jul 25, 201530 galRoot Intrusion—Street/Curb and Gutter
Jul 12, 201512 galGrease / FOG—Street/Curb and Gutter
Jul 10, 201528 galRoot Intrusion—Street/Curb and Gutter
Jul 5, 201537 galRoot Intrusion—Unpaved surface
Apr 19, 20152K galRoot IntrusionYesSurface Water
Mar 30, 201510 galGrease / FOG—Paved Surface;Street/Curb and Gutter;Unpaved surface
Mar 3, 2015150 galRoot Intrusion—Separate Storm Drain
Feb 8, 201536K galOther / UnknownYesDrainage Channel
Dec 30, 201455 galOther / Unknown—Separate Storm Drain
Dec 16, 201475K galOther / UnknownYesDrainage Channel
Dec 15, 2014186K galOther / UnknownYesDrainage Channel
Dec 11, 20142K galOther / UnknownYesSeparate Storm Drain
Dec 11, 2014360K galOther / UnknownYesDrainage Channel
Dec 11, 201454K galOther / UnknownYesSeparate Storm Drain
Dec 11, 20142K galOther / UnknownYesSeparate Storm Drain
Dec 11, 20141K galOther / UnknownYesSeparate Storm Drain
Dec 11, 20141K galRainfall / FloodingYesCombined Storm Drain (Combined CS only)
Dec 8, 2014152 galGrease / FOG—Other (specify below)
Dec 3, 201410K galOther / UnknownYesSeparate Storm Drain
Dec 3, 2014320 galRainfall / FloodingYesSeparate Storm Drain
Dec 2, 2014500 galCapacity IssueYesStreet/Curb and Gutter
Oct 30, 201420 galGrease / FOG—Building or Structure
Oct 16, 2014108 galGrease / FOG—Paved Surface;Street/Curb and Gutter
Oct 13, 2014375 galEquipment FailureYesSurface Water
Oct 2, 20144K galEquipment Failure—Unpaved surface
Sep 30, 2014155 galRoot Intrusion—Street/Curb and Gutter

Source: California (CIWQS). Volumes are utility-reported estimates. Some events lack precise coordinates or volumes.