Lake Notice Lake & river toxic algae advisories

San Diego County: lake and river algae advisories

67 waters in San Diego County appear in the state's harmful algal bloom records. Waters whose latest record is an advisory come first.

WaterLatest record
Agua Hedionda CreekAlgal mat alert sign, last posted Aug 24, 2023. No all-clear recorded.
Black Mountain CreekAlgal mat alert sign, last posted Aug 24, 2023. No all-clear recorded.
Evan's PondCaution advisory, last posted Jul 25, 2019. No all-clear recorded.
Guajome LakeGeneral awareness, last posted Mar 5, 2026. No all-clear recorded.
Heritage ParkWarning advisory, last posted Jul 12, 2024. No all-clear recorded.
Juaquapin CreekAlgal mat alert sign, last posted May 18, 2023. No all-clear recorded.
Kit Carson Park Eagle Scout LakeCaution advisory, last posted Aug 25, 2026. No all-clear recorded.
Lake HenshawCaution advisory, last posted Dec 28, 2022. No all-clear recorded.
Lake HodgesCaution advisory, last posted May 24, 2019. No all-clear recorded.
Lake MorenaCaution advisory, last posted Jul 1, 2021. No all-clear recorded.
Lake O'NeillGeneral awareness, last posted Jul 1, 2026. No all-clear recorded.
Lake San MarcosWarning advisory, last posted Jul 14, 2023. No all-clear recorded.
Lindo LakeDanger advisory, last posted Aug 28, 2024. No all-clear recorded.
Lower Otay ReservoirWarning advisory, last posted Jul 11, 2025. No all-clear recorded.
Miramar ReservoirCaution advisory, last posted Oct 2, 2026. No all-clear recorded.
Morena ReservoirCaution advisory, last posted Sep 21, 2026. No all-clear recorded.
Private pondCaution advisory, last posted Mar 11, 2026. No all-clear recorded.
San Diego RiverWarning advisory, last posted Aug 25, 2023. No all-clear recorded.
San Dieguito RiverAlgal mat alert sign, last posted Aug 25, 2023. No all-clear recorded.
Santa Margarita RiverGeneral awareness, last posted Oct 19, 2022. No all-clear recorded.
Santee LakesWarning advisory, last posted Dec 18, 2025. No all-clear recorded.
Santee Lakes #5Warning advisory, last posted Sep 17, 2025. No all-clear recorded.
Viejas Creek Spring PondCaution advisory, last posted Mar 27, 2023. No all-clear recorded.
Whelan LakeDanger advisory, last posted Aug 25, 2026. No all-clear recorded.
Agua Caliente CreekThe state's latest record, from Jul 25, 2023, recommends no advisory.
Agua Hedionda LagoonThe state's latest record, from Sep 18, 2020, recommends no advisory.
All Seasons RV ParkThe state's latest record, from Sep 17, 2025, recommends no advisory.
Anthony’s fish grottoThe state's latest record, from Jul 30, 2026, recommends no advisory.
Barrett ReservoirThe state's latest record, from May 27, 2020, recommends no advisory.
Big Laguna LakeThe state's latest record, from Aug 25, 2022, recommends no advisory.
Boulder CreekThe state's latest record, from Aug 25, 2023, recommends no advisory.
Cedar CreekThe state's latest record, from May 19, 2025, recommends no advisory.
Cedar Creek FallsThe state's latest record, from May 11, 2026, recommends no advisory.
Chollas CreekThe state's latest record, from Oct 13, 2026, recommends no advisory.
Chollas LakeThe state's latest record, from Dec 13, 2022, recommends no advisory.
Cold StreamThe state's latest record, from May 18, 2023, recommends no advisory.
Cuyamaca ReservoirThe state's latest record, from Jun 1, 2022, recommends no advisory.
Doane CreekThe state's latest record, from Jul 25, 2023, recommends no advisory.
Escondido CreekThe state's latest record, from Aug 25, 2022, recommends no advisory.
Espinosa CreekThe state's latest record, from Jul 25, 2023, recommends no advisory.
Famosa SloughThe state's latest record, from Oct 13, 2026, recommends no advisory.
Fenton PondThe state's latest record, from Sep 9, 2024, recommends no advisory.
Harper CreekThe state's latest record, from Jul 25, 2023, recommends no advisory.
Harveston LakeThe state's latest record, from Nov 3, 2025, recommends no advisory.
Hollister PondThe state's latest record, from Sep 9, 2024, recommends no advisory.
Japacha CreekThe state's latest record, from May 18, 2023, recommends no advisory.
Kitchen CreekThe state's latest record, from Jun 11, 2024, recommends no advisory.
Kumeyaay LakeThe state's latest record, from Oct 21, 2025, recommends no advisory.
Lake CalaveraReports on file, with no advisory level the state has classified.
Lake samagatumaReports on file, with no advisory level the state has classified.
Libby LakeThe state's latest record, from Aug 28, 2024, recommends no advisory.
Los Jilgueros Preserve PondsThe state's latest record, from Apr 2, 2024, recommends no advisory.
Los Penasquitos CreekThe state's latest record, from Jul 1, 2021, recommends no advisory.
Los Rasales LakeThe state's latest record, from Aug 25, 2022, recommends no advisory.
Mission BayThe state's latest record, from Oct 13, 2026, recommends no advisory.
Moosa Canyon pondThe state's latest record, from Sep 18, 2025, recommends no advisory.
Oceanside HarborThe state recorded an end date of Dec 30, 2022.
Pacific OceanThe state recorded an end date of Dec 30, 2022.
Palacio Del Mar EstateThe state's latest record, from Sep 14, 2022, recommends no advisory.
Pine Valley CreekThe state's latest record, from Jul 25, 2023, recommends no advisory.
San Felipe CreekThe state's latest record, from May 18, 2023, recommends no advisory.
San Luis Rey River estuaryThe state's latest record, from Aug 22, 2024, recommends no advisory.
San Onofre CreekThe state's latest record, from Jan 3, 2023, recommends no advisory.
San Vicente ReservoirReports on file, with no advisory level the state has classified.
Stonewall CreekThe state's latest record, from Jul 25, 2023, recommends no advisory.
Sweetwater RiverThe state's latest record, from Aug 25, 2025, recommends no advisory.
Unnamed Retention BasinReports on file, with no advisory level the state has classified.