Florida
Toxic algae in Osceola County lakes
10 lakes and waterways in Osceola County have harmful algal bloom reports in Florida's official data. The most recent entry is for Lake Marian: Florida's most recent sample from Lake Marian, on 3 December 2025 at Lake Marian - Pavilion, found a bloom and microcystin toxin measured 3.4 µg/L, below the US EPA swimming advisory level of 8 µg/L. Lake Marian and Fish Lake 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.
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.
- Jane Green Creek 2018
- Lake Rianhard 2019
- Lake Runnymede 2022
- Lake Tohopekaliga 2025
Source: Florida Department of Environmental Protection (DEP), official data, checked 24 October 2026. For today's conditions see the DEP Algal Bloom Dashboard. No report doesn't mean a lake is safe: most water is only tested occasionally.