California
Toxic algae in Sacramento County lakes
31 lakes and waterways in Sacramento County have harmful algal bloom reports in California's official data. The most recent entry is for Private Pond: A bloom was reported at Private Pond on 5 October 2026 at Rio Linda unknown location. Sacramento River, Lake Natoma and Three Mile Slough and 2 more have had blooms in three or more years.
Lakes with bloom history
Newest report first. Each lake has its own page with the full history and what the results mean.
- Private Pond Bloom reported
- Gibson Lake Bloom reported
- Pocket Canal Caution
- Sacramento River Bloom reported
- Lake Natoma Bloom reported
- Mokelumne River Bloom reported
- Three Mile Slough Bloom reported
- Camden Lake Warning
- Sherman Lake Caution
- South Fork Mokelumne River Bloom reported
- Sevenmile Slough Caution
- Laguna Creek Bloom reported
- Other River Bloom reported
- Stone Lakes Bloom reported
Other waterbodies with a report
These have one or two reports in a single year, which isn't enough history for a page of their own yet.
- Arcade Lake 2018
- Camden Lakes 2019
- Cosumnes River 2016
- Elk Grove Regional Park Lake 2026
- Hinkle Creek 2026
- Lower American River 2024
- Mather Lake 2025
- North Laguna Pond 2022
- North Natomas Retention Basin 2025
- Other Lake Or Reservoir 2021
- Peace Pond 2025
- San Juan Reservoir 2024
- Steamboat Slough 2020
- Tanzanite Park Pond 2026
- Turtle Pond 2026
- Washington Lake 2018
- Willow Creek 2025
Source: California State Water Resources Control Board, official data, checked 24 October 2026. For today's conditions see the California HABs Portal map. No report doesn't mean a lake is safe: most water is only tested occasionally.