MAPLE VALLEY, Wash. — Last week, Aug. 7, King County Public Health officials put out a formal warning against swimming in Lake Wilderness.
According to a King County Freshwater Beaches alert, the water tested positive for high amounts of microcystin, a toxic substance released from algae.
King County urges people to avoid swimming, drinking from the lake, and any other activities in or on the water.
They also highly recommend keeping pets away from the water, as the EPA notes microcystin can kill pets.
Waters are tested weekly, and if levels go down, results will be available on King County’s website.
©2026 Cox Media Group
