All rankings
California · California (CIWQS)
Los Altos City
A
Rarely reaches water
Reported events
143
Total volume
28K gal
Reached waterways
6 (4%)
Reporting since
2007
What caused the overflows
Root Intrusion
76
Grease / FOG
31
Equipment Failure
23
Other / Unknown
13
Reported overflow events (showing 143 of 143)
| Date | Volume | Cause | Reached water | Receiving water |
|---|---|---|---|---|
| Mar 26, 2026 | 175 gal | Grease / FOG | — | — |
| Oct 6, 2025 | 79 gal | Root Intrusion | — | — |
| Nov 2, 2024 | 199 gal | Root Intrusion | — | — |
| Jul 9, 2024 | 65 gal | Root Intrusion | — | — |
| Mar 9, 2024 | 55 gal | Grease / FOG | — | — |
| Sep 6, 2023 | 2K gal | Grease / FOG | — | — |
| Jul 15, 2023 | 142 gal | Grease / FOG | — | — |
| Jun 3, 2023 | 843 gal | Root Intrusion | — | — |
| Mar 24, 2023 | 50 gal | Root Intrusion | Yes | Drainage Channel |
| Mar 9, 2023 | 20 gal | Root Intrusion | — | Building or Structure;Unpaved surface |
| Feb 27, 2023 | 19 gal | Equipment Failure | — | Building or Structure;Paved Surface |
| Nov 30, 2022 | 5 gal | Root Intrusion | — | Unpaved surface |
| Nov 29, 2022 | 50 gal | Equipment Failure | — | Separate Storm Drain |
| Nov 25, 2022 | 5 gal | Root Intrusion | — | Unpaved surface |
| Nov 17, 2022 | 3 gal | Root Intrusion | — | Unpaved surface |
| Oct 11, 2022 | 3 gal | Grease / FOG | — | Building or Structure;Other (specify below) |
| Sep 23, 2022 | 10 gal | Root Intrusion | — | Street/Curb and Gutter |
| Aug 19, 2022 | 71 gal | Root Intrusion | — | Unpaved surface |
| Jul 7, 2022 | 8 gal | Root Intrusion | — | Street/Curb and Gutter |
| Jun 4, 2022 | 25 gal | Root Intrusion | — | Other (specify below) |
| May 16, 2022 | 98 gal | Grease / FOG | — | Street/Curb and Gutter |
| Jan 8, 2022 | 100 gal | Grease / FOG | — | Paved Surface |
| Nov 27, 2021 | 5 gal | Grease / FOG | — | Paved Surface |
| Nov 3, 2021 | 25 gal | Root Intrusion | — | Street/Curb and Gutter |
| Aug 18, 2021 | 30 gal | Root Intrusion | — | Unpaved surface |
| Jul 3, 2021 | 15 gal | Root Intrusion | — | Unpaved surface |
| Jun 18, 2021 | 20 gal | Root Intrusion | — | Unpaved surface |
| May 28, 2021 | 20 gal | Root Intrusion | — | Paved Surface |
| May 22, 2021 | 5 gal | Equipment Failure | — | Unpaved surface |
| Mar 11, 2021 | 20 gal | Root Intrusion | — | Building or Structure;Unpaved surface |
| Jan 25, 2021 | 150 gal | Root Intrusion | — | Unpaved surface |
| Jan 9, 2021 | 10 gal | Root Intrusion | — | Paved Surface |
| Oct 16, 2020 | 45 gal | Equipment Failure | — | Unpaved surface |
| May 14, 2020 | 15 gal | Root Intrusion | — | Unpaved surface |
| Mar 30, 2020 | 500 gal | Root Intrusion | — | Other (specify below) |
| Feb 11, 2020 | 1K gal | Grease / FOG | — | Separate Storm Drain |
| Feb 4, 2020 | 26 gal | Root Intrusion | — | Unpaved surface |
| Feb 1, 2020 | 3K gal | Root Intrusion | — | Building or Structure |
| Jan 31, 2020 | 20 gal | Root Intrusion | — | Paved Surface |
| Nov 6, 2019 | 5 gal | Equipment Failure | — | Unpaved surface |
| Oct 25, 2019 | 10 gal | Root Intrusion | — | Building or Structure;Paved Surface |
| Oct 25, 2019 | — | Root Intrusion | — | Building or Structure;Paved Surface |
| Apr 24, 2019 | 10 gal | Root Intrusion | — | Building or Structure;Paved Surface |
| Mar 31, 2019 | 140 gal | Root Intrusion | — | Separate Storm Drain |
| Mar 12, 2019 | 5 gal | Equipment Failure | — | Unpaved surface |
| Dec 17, 2018 | 2K gal | Root Intrusion | — | Unpaved surface |
| Nov 20, 2018 | 10 gal | Root Intrusion | — | Unpaved surface |
| Nov 19, 2018 | 5 gal | Root Intrusion | — | Unpaved surface |
| Aug 13, 2018 | 50 gal | Root Intrusion | — | Paved Surface |
| Mar 25, 2018 | 5 gal | Equipment Failure | — | Building or Structure |
| Jan 29, 2018 | 25 gal | Root Intrusion | — | Street/Curb and Gutter |
| Nov 22, 2017 | 50 gal | Root Intrusion | — | Separate Storm Drain |
| Aug 23, 2017 | 5 gal | Grease / FOG | — | Building or Structure;Unpaved surface |
| Jun 11, 2017 | 10 gal | Equipment Failure | — | Paved Surface |
| May 30, 2017 | 50 gal | Grease / FOG | — | Unpaved surface |
| May 23, 2017 | 15 gal | Grease / FOG | — | Separate Storm Drain;Street/Curb and Gutter |
| Mar 27, 2017 | 150 gal | Equipment Failure | — | Separate Storm Drain |
| Mar 23, 2017 | 5 gal | Root Intrusion | — | Paved Surface;Unpaved surface |
| Mar 20, 2017 | 7 gal | Root Intrusion | — | Paved Surface;Unpaved surface |
| Feb 13, 2017 | 10 gal | Root Intrusion | — | Unpaved surface |
| Jan 8, 2017 | 10 gal | Root Intrusion | — | Unpaved surface |
| Nov 18, 2016 | 750 gal | Grease / FOG | — | Separate Storm Drain |
| Aug 13, 2016 | 10 gal | Root Intrusion | — | Unpaved surface |
| Jul 15, 2016 | 2 gal | Root Intrusion | — | Unpaved surface |
| Apr 9, 2016 | 2K gal | Root Intrusion | — | Other (specify below) |
| Mar 10, 2016 | 52 gal | Root Intrusion | — | Street/Curb and Gutter |
| Mar 5, 2016 | 22 gal | Equipment Failure | — | Paved Surface |
| Mar 4, 2016 | 525 gal | Root Intrusion | — | Separate Storm Drain |
| Feb 28, 2016 | 80 gal | Equipment Failure | — | Unpaved surface |
| Dec 31, 2015 | 720 gal | Equipment Failure | Yes | Drainage Channel |
| Dec 15, 2015 | 60 gal | Root Intrusion | — | Separate Storm Drain |
| Nov 12, 2015 | 10 gal | Root Intrusion | — | Building or Structure |
| Jul 19, 2015 | 50 gal | Grease / FOG | — | Building or Structure;Unpaved surface |
| Jun 26, 2015 | 15 gal | Root Intrusion | — | Other (specify below) |
| Jun 3, 2015 | 10 gal | Root Intrusion | — | Unpaved surface |
| May 25, 2015 | 250 gal | Grease / FOG | Yes | Drainage Channel |
| Mar 3, 2015 | 300 gal | Root Intrusion | — | Unpaved surface |
| Feb 24, 2015 | 10 gal | Grease / FOG | — | Paved Surface |
| Jan 28, 2015 | 2 gal | Root Intrusion | — | Other (specify below) |
| Jan 26, 2015 | 10 gal | Equipment Failure | — | Unpaved surface |
| Jan 17, 2015 | 15 gal | Equipment Failure | — | Unpaved surface |
| Jan 16, 2015 | 10 gal | Root Intrusion | — | Unpaved surface |
| Dec 23, 2014 | 10 gal | Grease / FOG | — | Unpaved surface |
| Oct 19, 2014 | 711 gal | Root Intrusion | — | Separate Storm Drain |
| Oct 3, 2014 | 125 gal | Root Intrusion | — | Separate Storm Drain |
| Sep 30, 2014 | 125 gal | Grease / FOG | Yes | Drainage Channel |
| Sep 25, 2014 | 800 gal | Root Intrusion | — | Unpaved surface |
| Sep 20, 2014 | 35 gal | Root Intrusion | — | Building or Structure;Unpaved surface |
| Sep 12, 2014 | 75 gal | Grease / FOG | — | Separate Storm Drain |
| Aug 31, 2014 | 5 gal | Grease / FOG | — | Paved Surface |
| Aug 1, 2014 | 200 gal | Root Intrusion | — | Separate Storm Drain |
| Jul 22, 2014 | 375 gal | Root Intrusion | — | Separate Storm Drain |
| Jun 27, 2014 | 15 gal | Root Intrusion | — | Street/Curb and Gutter |
| Jun 9, 2014 | 10 gal | Root Intrusion | — | Paved Surface |
| May 25, 2014 | 10 gal | Equipment Failure | Yes | Drainage Channel |
| Apr 14, 2014 | 375 gal | Root Intrusion | — | Separate Storm Drain |
| Apr 14, 2014 | 15 gal | Grease / FOG | — | Unpaved surface |
| Mar 4, 2014 | 100 gal | Root Intrusion | — | Unpaved surface |
| Feb 5, 2014 | 25 gal | Root Intrusion | — | Other (specify below) |
| Jan 12, 2014 | 8 gal | Grease / FOG | — | Unpaved surface |
| Dec 20, 2013 | 35 gal | Grease / FOG | — | Building or Structure;Unpaved surface |
| Oct 7, 2013 | 165 gal | Grease / FOG | — | Unpaved surface |
| Jul 22, 2013 | 60 gal | Grease / FOG | — | Other (specify below) |
| May 9, 2013 | 42 gal | Other / Unknown | — | Unpaved surface |
| Apr 21, 2013 | 50 gal | Grease / FOG | — | Unpaved surface |
| Mar 13, 2013 | 333 gal | Grease / FOG | — | Separate storm drain |
| Dec 2, 2012 | 6K gal | Root Intrusion | — | Building or structure |
| Aug 23, 2012 | 10 gal | Equipment Failure | — | Building or structure |
| Aug 14, 2012 | 25 gal | Equipment Failure | — | Building or structure;Other paved surface |
| Aug 22, 2011 | 2 gal | Other / Unknown | — | Building or structure |
| Jul 26, 2011 | 60 gal | Root Intrusion | — | Unpaved surface |
| Dec 23, 2010 | 680 gal | Other / Unknown | — | Other paved surface |
| Nov 24, 2010 | 25 gal | Grease / FOG | — | Other paved surface;Other (specify below) |
| Nov 12, 2010 | 10 gal | Root Intrusion | — | Building or structure;Street/curb and gutter |
| Oct 29, 2010 | 35 gal | Grease / FOG | Yes | Other (specify below) |
| May 15, 2010 | 275 gal | Root Intrusion | — | Other (specify below) |
| Mar 19, 2010 | 35 gal | Other / Unknown | — | Separate storm drain |
| Nov 4, 2009 | 100 gal | Other / Unknown | — | Unpaved surface |
| Nov 3, 2009 | 2 gal | Root Intrusion | — | Other paved surface |
| Oct 29, 2009 | 10 gal | Equipment Failure | — | Other paved surface |
| Oct 20, 2009 | 3 gal | Root Intrusion | — | Building or structure;Unpaved surface |
| Oct 18, 2009 | 5 gal | Other / Unknown | — | Other paved surface |
| Oct 6, 2009 | 40 gal | Root Intrusion | — | Unpaved surface |
| Jun 26, 2009 | 36 gal | Root Intrusion | — | Storm drain |
| Mar 24, 2009 | 5 gal | Root Intrusion | — | Unpaved surface |
| Mar 18, 2009 | 75 gal | Other / Unknown | — | Unpaved surface |
| Mar 15, 2009 | 60 gal | Equipment Failure | — | Unpaved surface |
| Mar 15, 2009 | 60 gal | Other / Unknown | — | Unpaved surface |
| Jan 21, 2009 | 180 gal | Grease / FOG | — | Storm drain |
| Jan 8, 2009 | 5 gal | Other / Unknown | — | Unpaved surface |
| Dec 31, 2008 | 40 gal | Grease / FOG | — | Street/curb and gutter;Unpaved surface |
| Dec 9, 2008 | 5 gal | Equipment Failure | — | Unpaved surface |
| Dec 4, 2008 | 60 gal | Equipment Failure | — | Unpaved surface |
| Nov 24, 2008 | 60 gal | Equipment Failure | — | Unpaved surface |
| Nov 18, 2008 | 4 gal | Other / Unknown | — | Building or structure;Unpaved surface |
| Oct 9, 2008 | 10 gal | Root Intrusion | — | Unpaved surface |
| Sep 29, 2008 | 3 gal | Other / Unknown | — | Building or structure |
| Aug 21, 2008 | 5 gal | Other / Unknown | — | Other paved surface |
| Jul 15, 2008 | 5 gal | Root Intrusion | — | Unpaved surface |
| Nov 11, 2007 | 15 gal | Equipment Failure | — | Unpaved surface |
| Oct 14, 2007 | 20 gal | Root Intrusion | — | Unpaved surface |
| Aug 23, 2007 | 80 gal | Other / Unknown | — | Unpaved surface |
| Jun 4, 2007 | 420 gal | Root Intrusion | — | Other paved surface;Unpaved surface;Other (specify below) |
Source: California (CIWQS). Volumes are utility-reported estimates. Some events lack precise coordinates or volumes.