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California · California (CIWQS)

West Valley SD

B
Seldom reaches water
Reported events
333
Total volume
203K gal
Reached waterways
46 (14%)
Reporting since
2007

What caused the overflows

Root Intrusion
158
Other / Unknown
64
Equipment Failure
54
Grease / FOG
48
Rainfall / Flooding
7
Capacity Issue
2

Reported overflow events (showing 200 of 333)

DateVolumeCauseReached waterReceiving water
May 16, 20269K galRoot IntrusionYesRoss Creek
Jan 4, 2026952 galEquipment FailureYesLos Gatos Creek
Jan 1, 20263K galGrease / FOGYesRoss Creek
Dec 21, 2025818 galEquipment Failure——
Oct 6, 2025304 galRoot Intrusion——
Oct 2, 202569 galGrease / FOG——
Aug 19, 2025145 galRoot Intrusion——
Mar 6, 2025670 galOther / UnknownYesRoss Creek
Mar 6, 2025675 galOther / UnknownYesRoss Creek
Dec 17, 20246K galGrease / FOGYesShort Creek
Dec 17, 20247K galGrease / FOGYesShort Creek
Dec 11, 202416K galGrease / FOGYesSmith Creek
Jul 18, 20243K galEquipment Failure——
May 27, 20242K galRoot Intrusion——
Sep 26, 2023305 galGrease / FOG——
Jul 20, 2023259 galRoot Intrusion——
May 26, 202313 galEquipment Failure—Street/Curb and Gutter
May 25, 20233 galRoot Intrusion—Building or Structure
May 3, 2023249 galRoot Intrusion—Street/Curb and Gutter;Unpaved surface
Mar 29, 20233 galEquipment Failure—Building or Structure
Dec 18, 202222 galGrease / FOG—Paved Surface;Street/Curb and Gutter
Dec 13, 2022839 galRoot IntrusionYesSurface Water;Unpaved surface
Dec 11, 202210 galRainfall / Flooding—Unpaved surface
Nov 25, 2022205 galEquipment Failure—Unpaved surface
Sep 10, 20222K galEquipment Failure—Other (specify below);Paved Surface
Jul 1, 202252 galRoot Intrusion—Paved Surface
Jun 10, 20222K galEquipment FailureYesDrainage Channel;Unpaved surface
Mar 1, 202210 galRoot Intrusion—Building or Structure
Feb 25, 2022940 galGrease / FOG—Building or Structure;Paved Surface;Separate Storm Drain;Street/Curb and Gutter
Feb 15, 202214 galEquipment Failure—Paved Surface
Jan 28, 2022642 galEquipment Failure—Street/Curb and Gutter;Unpaved surface
Jan 17, 202219 galRoot Intrusion—Building or Structure;Unpaved surface
Jan 14, 20221K galEquipment Failure—Paved Surface;Separate Storm Drain;Street/Curb and Gutter
Nov 19, 20215 galRoot Intrusion—Street/Curb and Gutter;Unpaved surface
Nov 12, 202199 galRoot Intrusion—Other (specify below);Unpaved surface
Sep 10, 202129 galRoot Intrusion—Separate Storm Drain;Street/Curb and Gutter
May 20, 20211K galGrease / FOG—Separate Storm Drain;Street/Curb and Gutter
Apr 15, 202159 galEquipment Failure—Unpaved surface
Apr 5, 202117 galGrease / FOG—Street/Curb and Gutter
Mar 4, 202168 galGrease / FOG—Street/Curb and Gutter
Nov 9, 202034 galOther / Unknown—Paved Surface;Separate Storm Drain
Nov 7, 202071 galGrease / FOG—Building or Structure
Sep 13, 2020446 galRoot Intrusion—Unpaved surface
Aug 18, 2020907 galOther / Unknown—Paved Surface;Separate Storm Drain;Street/Curb and Gutter;Unpaved surface
Apr 27, 20201 galRoot Intrusion—Street/Curb and Gutter
Jan 4, 20206K galRoot Intrusion—Drainage Channel;Unpaved surface
Dec 4, 2019125 galRoot Intrusion—Building or Structure;Unpaved surface
Nov 20, 20191K galRoot Intrusion—Paved Surface;Unpaved surface
Mar 17, 201920 galEquipment Failure—Building or Structure
Feb 15, 20191K galCapacity IssueYesDrainage Channel;Paved Surface;Separate Storm Drain;Street/Curb and Gutter
Feb 14, 201932K galRainfall / FloodingYesDrainage Channel;Separate Storm Drain;Street/Curb and Gutter;Surface Water
Feb 14, 20195K galOther / Unknown—Paved Surface;Unpaved surface
Jan 2, 2019203 galGrease / FOG—Paved Surface;Street/Curb and Gutter
Dec 22, 2018172 galRoot Intrusion—Paved Surface;Street/Curb and Gutter
Oct 25, 2018600 galGrease / FOGYesSeparate Storm Drain;Unpaved surface
Oct 16, 2018156 galRoot Intrusion—Paved Surface;Separate Storm Drain;Street/Curb and Gutter
Sep 3, 201820 galGrease / FOG—Paved Surface;Street/Curb and Gutter
Aug 27, 201820 galEquipment Failure—Building or Structure;Unpaved surface
Aug 13, 20183K galEquipment Failure—Street/Curb and Gutter;Unpaved surface
Jul 29, 2018340 galEquipment Failure—Building or Structure;Unpaved surface
Jul 7, 201850 galEquipment Failure—Unpaved surface
Apr 2, 2018430 galRoot IntrusionYesDrainage Channel;Paved Surface;Street/Curb and Gutter;Surface Water
Oct 24, 201793 galEquipment Failure—Unpaved surface
Oct 9, 2017156 galRoot Intrusion—Street/Curb and Gutter
Aug 28, 2017101 galEquipment Failure—Unpaved surface
Aug 23, 2017792 galEquipment Failure—Building or Structure
May 21, 201750 galGrease / FOG—Building or Structure
Apr 13, 2017500 galGrease / FOG—Separate Storm Drain;Street/Curb and Gutter
Apr 4, 20172 galEquipment Failure—Building or Structure
Mar 20, 20171 galRoot Intrusion—Building or Structure
Feb 16, 201775 galEquipment Failure—Unpaved surface
Feb 7, 20175K galRainfall / FloodingYesSurface Water
Jan 27, 201730 galGrease / FOG—Street/Curb and Gutter
Jan 8, 2017250 galRainfall / Flooding—Building or Structure;Paved Surface
Jan 1, 201715 galRoot Intrusion—Building or Structure
Dec 28, 201625 galRoot Intrusion—Street/Curb and Gutter
Dec 14, 2016100 galEquipment Failure—Unpaved surface
Dec 8, 20167 galEquipment Failure—Paved Surface
Nov 14, 201625 galRoot Intrusion—Street/Curb and Gutter
Nov 2, 201610 galRoot Intrusion—Street/Curb and Gutter
Sep 29, 2016112 galRoot Intrusion—Street/Curb and Gutter
Jun 4, 2016200 galRoot Intrusion—Paved Surface
Jun 4, 20165K galOther / UnknownYesSurface Water
Feb 24, 2016215 galEquipment Failure—Street/Curb and Gutter
Feb 22, 201625 galRoot Intrusion—Building or Structure
Feb 17, 2016500 galEquipment Failure—Unpaved surface
Feb 5, 2016136 galRoot Intrusion—Street/Curb and Gutter
Feb 1, 2016238 galEquipment Failure—Paved Surface
Jan 19, 20164K galRoot IntrusionYesDrainage Channel
Jan 4, 2016200 galRoot Intrusion—Street/Curb and Gutter
Dec 4, 2015200 galGrease / FOGYesSurface Water
Oct 20, 201520 galRoot Intrusion—Unpaved surface
Sep 23, 201515 galRoot Intrusion—Building or Structure
Aug 4, 2015261 galRoot Intrusion—Paved Surface;Unpaved surface
Aug 3, 20152 galRoot Intrusion—Building or Structure
May 30, 2015309 galEquipment Failure—Paved Surface;Separate Storm Drain;Street/Curb and Gutter
Apr 6, 20151K galOther / UnknownYesSurface Water
Mar 21, 201540 galRoot Intrusion—Unpaved surface
Feb 26, 201540 galRoot Intrusion—Paved Surface
Feb 19, 2015498 galEquipment Failure—Building or Structure
Feb 12, 201511 galRoot Intrusion—Street/Curb and Gutter
Feb 4, 2015100 galRoot Intrusion—Paved Surface
Jan 1, 20151 galRoot Intrusion—Building or Structure
Dec 23, 201462 galRoot Intrusion—Unpaved surface
Dec 8, 2014159 galRoot Intrusion—Street/Curb and Gutter
Dec 2, 20142K galEquipment FailureYesSurface Water
Nov 28, 201450 galRoot Intrusion—Other (specify below)
Nov 5, 201445 galRoot Intrusion—Street/Curb and Gutter
Nov 3, 201435 galEquipment Failure—Unpaved surface
Oct 19, 201410 galEquipment Failure—Building or Structure
Oct 14, 201486 galRoot Intrusion—Street/Curb and Gutter
Oct 2, 201485 galRoot Intrusion—Street/Curb and Gutter
Sep 26, 2014312 galRoot IntrusionYesDrainage Channel
Jul 29, 2014785 galRoot IntrusionYesDrainage Channel
Jun 4, 201423 galRoot Intrusion—Paved Surface
May 2, 201425 galEquipment Failure—Building or Structure;Paved Surface
Apr 24, 2014718 galGrease / FOG—Unpaved surface
Apr 2, 2014153 galEquipment Failure—Paved Surface;Street/Curb and Gutter
Feb 22, 201475 galEquipment Failure—Street/Curb and Gutter
Jan 14, 201456 galEquipment Failure—Street/Curb and Gutter
Dec 31, 20138K galOther / UnknownYesDrainage Channel;Unpaved surface
Dec 26, 20133K galRoot IntrusionYesDrainage Channel;Separate Storm Drain;Street/Curb and Gutter;Unpaved surface
Dec 6, 201316 galEquipment Failure—Street/Curb and Gutter
Dec 5, 201310 galRoot Intrusion—Paved Surface;Street/Curb and Gutter;Unpaved surface
Dec 1, 20132 galRoot Intrusion—Building or Structure
Nov 15, 20131K galRoot IntrusionYesSeparate Storm Drain;Street/Curb and Gutter;Surface Water
Sep 19, 20131K galOther / UnknownYesDrainage Channel;Unpaved surface
Aug 23, 2013100 galGrease / FOGYesUnpaved surface
Apr 7, 201316 galGrease / FOG—Street/curb and gutter
Mar 25, 20131 galOther / Unknown—Building or structure
Mar 5, 2013100 galRoot Intrusion—Street/curb and gutter
Feb 26, 2013244 galGrease / FOG—Unpaved surface
Feb 15, 20135 galOther / Unknown—Building or structure
Feb 6, 2013120 galRoot Intrusion—Unpaved surface
Jan 21, 2013200 galOther / Unknown—Other (specify below)
Dec 29, 2012254 galOther / Unknown—Unpaved surface
Dec 22, 2012800 galOther / UnknownYesOther paved surface;Surface water;Unpaved surface
Dec 18, 2012150 galRoot Intrusion—Street/curb and gutter
Dec 2, 2012200 galOther / Unknown—Building or structure;Street/curb and gutter
Nov 21, 201220 galGrease / FOG—Street/curb and gutter
Nov 9, 201220 galRoot Intrusion—Other paved surface;Unpaved surface
Oct 29, 201250 galRoot Intrusion—Separate storm drain
Oct 15, 201250 galRoot Intrusion—Street/curb and gutter
Sep 14, 201235 galRoot Intrusion—Building or structure
Aug 22, 20121 galRoot Intrusion—Street/curb and gutter
Aug 17, 201210 galGrease / FOG—Building or structure;Unpaved surface
Aug 16, 201220 galRoot Intrusion—Unpaved surface
Aug 5, 20125 galRoot Intrusion—Street/curb and gutter
Jul 26, 20121 galOther / Unknown—Building or structure
Jul 20, 201262 galRoot Intrusion—Separate storm drain;Street/curb and gutter
Jul 12, 2012210 galRoot Intrusion—Street/curb and gutter
Jun 21, 2012155 galRoot Intrusion—Unpaved surface
May 18, 2012155 galOther / Unknown—Other paved surface;Street/curb and gutter
May 18, 2012170 galOther / UnknownYesOther paved surface;Surface water;Unpaved surface
Apr 23, 201230 galGrease / FOG—Separate storm drain
Mar 20, 2012400 galRoot Intrusion—Street/curb and gutter;Unpaved surface
Mar 16, 20122K galRoot IntrusionYesSeparate storm drain;Street/curb and gutter;Surface water
Mar 10, 201250 galRoot Intrusion—Building or structure
Mar 9, 20125 galRoot Intrusion—Street/curb and gutter
Mar 8, 20125 galOther / Unknown—Street/curb and gutter
Mar 8, 201250 galEquipment Failure—Building or structure
Mar 6, 20121 galOther / Unknown—Unpaved surface
Feb 23, 20121 galOther / Unknown—Unpaved surface
Feb 19, 201215 galRoot Intrusion—Building or structure
Feb 11, 2012800 galGrease / FOGYesSeparate storm drain;Street/curb and gutter;Surface water
Feb 1, 20128 galOther / Unknown—Street/curb and gutter;Unpaved surface
Jan 25, 2012900 galGrease / FOG—Street/curb and gutter
Jan 7, 2012300 galGrease / FOG—Street/curb and gutter
Dec 23, 201110 galRoot Intrusion—Unpaved surface
Dec 6, 20111 galRoot Intrusion—Building or structure
Nov 29, 201130 galOther / Unknown—Other paved surface;Unpaved surface
Oct 25, 20111 galRoot Intrusion—Building or structure;Unpaved surface
Oct 16, 20116 galRoot Intrusion—Building or structure
Oct 2, 20113 galRoot Intrusion—Unpaved surface
Sep 2, 201120 galRoot Intrusion—Building or structure
Aug 10, 20113 galOther / Unknown—Unpaved surface
Jul 18, 20112 galRoot Intrusion—Unpaved surface
Jul 6, 20112 galRoot Intrusion—Unpaved surface
Jun 19, 20111 galOther / Unknown—Other paved surface
Jun 17, 2011250 galRoot Intrusion—Building or structure
Jun 17, 2011250 galRoot Intrusion—Building or structure
Jun 17, 20112 galOther / Unknown—Building or structure
Jun 6, 20115 galRoot Intrusion—Other paved surface;Street/curb and gutter
May 19, 201120 galRoot Intrusion—Unpaved surface
May 18, 2011275 galRoot Intrusion—Other (specify below)
May 18, 2011275 galRoot IntrusionYesSeparate storm drain;Street/curb and gutter
May 14, 20112 galRoot Intrusion—Unpaved surface
May 3, 201110 galRoot Intrusion—Unpaved surface
Apr 15, 20113 galRoot Intrusion—Unpaved surface
Mar 24, 2011100 galRainfall / FloodingYesSeparate storm drain;Street/curb and gutter
Mar 24, 201150 galRainfall / Flooding—Building or structure
Mar 24, 2011300 galRainfall / FloodingYesSeparate storm drain;Street/curb and gutter
Mar 23, 2011625 galGrease / FOG—Building or structure;Unpaved surface
Mar 23, 2011500 galGrease / FOGYesSurface water
Mar 21, 2011150 galRoot Intrusion—Street/curb and gutter;Other (specify below)
Mar 3, 20118K galRoot IntrusionYesOther paved surface;Separate storm drain;Street/curb and gutter;Surface water
Feb 28, 20111 galOther / Unknown—Building or structure
Feb 4, 20112 galOther / Unknown—Building or structure
Feb 3, 2011500 galGrease / FOG—Separate storm drain;Street/curb and gutter;Unpaved surface
Jan 19, 20115 galRoot Intrusion—Other paved surface;Unpaved surface

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