Contra Costa County: lake and river algae advisories
32 waters in Contra Costa County appear in the state's harmful algal bloom records. Waters whose latest record is an advisory come first.
| Water | Latest record |
|---|---|
| Antioch Dunes National Wildlife Refuge | Caution advisory, last posted Jul 21, 2021. No all-clear recorded. |
| Bethel Island | Caution advisory, last posted Aug 3, 2023. No all-clear recorded. |
| Big Break Regional Shoreline | Danger advisory, last posted Oct 9, 2026. No all-clear recorded. |
| Briones Regional Park | Visual observation, last posted Jan 13, 2025. No all-clear recorded. |
| Carquinez Strait | Danger advisory, last posted Jul 8, 2026. No all-clear recorded. |
| Contra Loma Reservoir | Caution advisory, last posted Dec 8, 2022. No all-clear recorded. |
| Delta Coves | Caution advisory, last posted Jul 27, 2026. No all-clear recorded. |
| Discovery Bay | Danger advisory, last posted Jul 8, 2026. No all-clear recorded. |
| Discovery Bay Marina | Caution advisory, last posted Jul 24, 2026. No all-clear recorded. |
| False River | Visual observation, last posted Nov 6, 2023. No all-clear recorded. |
| Fisherman's Cut | Visual observation, last posted Nov 6, 2023. No all-clear recorded. |
| Frank's Tract | Caution advisory, last posted Jul 21, 2022. No all-clear recorded. |
| Lake Anza | Danger advisory, last posted Jul 16, 2021. No all-clear recorded. |
| Los Vaqueros Reservoir | Visual observation, last posted Jul 6, 2023. No all-clear recorded. |
| Martinez Shoreline | Caution advisory, last posted Oct 16, 2026. No all-clear recorded. |
| Old River | Caution advisory, last posted Sep 17, 2026. No all-clear recorded. |
| San Francisco Bay, Central | Caution advisory, last posted Aug 1, 2023. No all-clear recorded. |
| San Joaquin River | Danger advisory, last posted Aug 3, 2022. No all-clear recorded. |
| San Pablo Bay | Visual observation, last posted Aug 1, 2023. No all-clear recorded. |
| San Ramon Creek | Caution advisory, last posted Oct 18, 2024. No all-clear recorded. |
| West Canal | Visual observation, last posted Sep 17, 2026. No all-clear recorded. |
| Antioch/Oakley Regional Shoreline | The state's latest record, from Dec 4, 2018, recommends no advisory. |
| Bear Creek | The state's latest record, from May 3, 2024, recommends no advisory. |
| Brentwood Golf Course | The state's latest record, from Oct 24, 2018, recommends no advisory. |
| Clifton Court Forebay | The state's latest record, from Oct 19, 2026, recommends no advisory. |
| Discovery Bay Golf and Country Club | Reports on file, with no advisory level the state has classified. |
| Martinez Marina | The state's latest record, from Sep 12, 2025, recommends no advisory. |
| Martinez Regional Shoreline Park | The state's latest record, from Sep 12, 2025, recommends no advisory. |
| McNabney Marsh | The state's latest record, from Oct 17, 2017, recommends no advisory. |
| Mokelumne River | The state's latest record, from Dec 4, 2018, recommends no advisory. |
| New York Slough | Reports on file, with no advisory level the state has classified. |
| San Joaquin-Sacramento River | Reports on file, with no advisory level the state has classified. |