Good news for swimmers and boaters: the recreational health advisory for Lake Billy Chinook has been downgraded from a full advisory to a precaution level, following recent water monitoring that showed cyanotoxin levels have fallen below recreational guideline values for people.

The Oregon Health Authority had issued the original recreational use advisory for the lake on June 12, after testing detected elevated levels of cyanotoxins — toxic substances produced by certain types of algae, also called cyanobacteria or blue-green algae.

What Changed — and What Hasn't

While toxin levels are now considered safe for most recreational use by people, a cyanobacteria bloom remains present in the lake. Toxin levels are still above the state's educational guideline values for dogs, and officials urged pet owners to keep animals away from any areas where blooms are visible.

Visitors should watch for water that appears:

  • Foamy or scummy on the surface
  • Thick like paint, pea-green, or blue-green in color
  • Containing thick brownish-red mats or bright green clumps

People and pets should avoid contact with those areas. Cyanotoxins can remain in clear water even after a bloom dissipates visually.

What This Means for Summer Recreation

Lake Billy Chinook, located at the confluence of the Deschutes, Metolius, and Crooked rivers within the Cove Palisades State Park area, is one of Jefferson County's most popular summer recreation destinations. The downgrade to precaution status means swimming, boating, waterskiing, and other water recreation can resume for people — but with awareness and caution.

Officials note that blooms can develop and disappear quickly, and only a fraction of Oregon water bodies are routinely monitored. Conditions can change rapidly during warm summer weather.

If You're Concerned

For health information or to report an illness potentially related to cyanotoxin exposure, contact the Oregon Health Authority at 971-673-0482. More information is also available on OHA's Cyanobacteria website at oregon.gov/OHA.

Residents can also sign up for alerts through Jefferson County's emergency notification system to stay informed about changes in water quality advisories throughout the summer.