Is Richardson Bay safe? Toxic algae status
Marin County, California. Harmful algal bloom (blue-green algae) reports from the California State Water Resources Control Board.
Data checked 24 October 2026. California data is updated daily.
7
bloom reports since 2017
3 of 7
years with a bloom reported (2017–2023)
0
advisories recommended: 0 Caution, 0 Warning, 0 Danger
Year by year
Each box shows bloom reports logged that year, coloured by the highest advisory recommended.
Reports at Richardson Bay are most often logged in April, May and July.
Recent reports
| Date | Location | Result |
|---|---|---|
| 30 July 2023 | Sausalito Yacht Harbor | Bloom reported |
| 29 July 2023 | Waldo Point Harbor | Bloom reported |
| 29 July 2023 | Spinnaker Restaurant | Bloom reported |
| 28 July 2023 | Galilee Harbor | Bloom reported |
| 19 May 2023 | Waldo Point Harbor at Issaquah dock | Bloom reported |
| 1 June 2020 | Richardson Bay, at Strawberry Lagoon | Bloom reported |
| 30 April 2017 | Richardson Bay, at Coyote Creek outlet | Bloom reported |
What the results mean
Algae may be present. Stay away from scum and discoloured water, and keep pets and livestock from drinking it.
Toxins at higher levels. No swimming, and keep pets and children well away from the water.
High toxin levels. Stay out of the water and off the shoreline.
Dogs and toxic algae
Dogs face the greatest risk because they swallow water and lick algae off their fur. If a bloom has been reported, keep dogs out of the water and away from scum on the shore. If your dog swims in water that might have algae, rinse it with clean water straight away and call a vet if it seems unwell.
Common questions
Is Richardson Bay safe to swim in?
The most recent entry in California's published data is from 30 July 2023: bloom reported (Sausalito Yacht Harbor). Blooms have been recorded at Richardson Bay in 3 different years, so treat green, scummy or discoloured water with caution. For current conditions, check the California HABs Portal map and posted signs.
When does Richardson Bay get algae blooms?
In the state's records, reports are most often logged in April, May and July. Blooms are most likely in warm, calm weather, but they can appear at other times of year.
Source: California State Water Resources Control Board, official data. This page is independent and not affiliated with the State of California.