Oregon

Toxic algae in Jefferson County lakes

3 lakes and waterways in Jefferson County have harmful algal bloom reports in Oregon's official data. The most recent entry is for Haystack Reservoir: Oregon issued a precaution for Haystack Reservoir in 2025, listed on 15 September 2025. Lake Billy Chinook 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.

Haystack Reservoir Latest 15 September 2025, blooms in 2 years Precaution
Lake Billy Chinook Latest 1 July 2025, blooms in 7 years Health advisory

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.

Lake Simtustus 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.