Toxic algae in Contra Costa County, California
20 lakes and waterways have harmful algal bloom reports in California's official data.
Lakes with bloom history
| Lake | Years with reports | Most recent |
|---|---|---|
| Discovery Bay | 11 | 2026 |
| Lake Anza | 8 | 2023 |
| Contra Loma Reservoir | 4 | 2023 |
| False River | 4 | 2023 |
| San Pablo Bay | 4 | 2024 |
| West Canal | 3 | 2023 |
| Los Vaqueros Reservoir | 3 | 2024 |
Other waterbodies with a report
These have one or two reports in a single year, so there isn't enough history for a page of their own yet.
- Alhambra Creek (2023)
- Bear Creek (2024)
- Canyon Lake Golf Course (2022)
- Cypress Grove Pond (2024)
- Discovery Bay Golf And Country Club (2025)
- Hidden Valley Lake (2024)
- Kellogg Creek (2020)
- Las Trampas Creek (2026)
- Mcnabney Marsh (2017)
- Moorhen Marsh (2023)
- New York Slough (2020)
- San Joaquin-Sacramento River (2026)
- San Ramon Creek (2024)
Source: California State Water Resources Control Board, official data. For current conditions see the California HABs Portal map.