Oregon
Toxic algae in Douglas County lakes
5 lakes and waterways in Douglas County have harmful algal bloom reports in Oregon's official data. The most recent entry is for South Umpqua River: Oregon issued a permanent advisory for South Umpqua River in 2025, listed on 1 July 2025. South Umpqua River has 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.
- Galesville Reservoir 2023
- Loon Lake 2025
Source: Oregon Health Authority (OHA), official data, checked 24 October 2026. For today's conditions see the OHA current advisories page. No report doesn't mean a lake is safe: most water is only tested occasionally.