Blue-green algae is back at Beaver Lake, leading to a swimming advisory for the area.
Adjoining Elk Lake is so far free of the algae, which continues to be a problem at Thetis Lake and has just disappeared at Prior Lake.
People visiting Beaver Lake are advised to keep animals leashed to prevent them from swimming in or drinking the water.
While the algae can produce a blue-green sheen on the water, toxins can still be in the water if no colour is visible.
Affected water can cause headaches and abdominal pain in humans, as well as fatal liver damage in dogs.
Fishing in areas with the algae is not considered harmful.
Glenn Harris, senior manager of environmental protection for the Capital Regional District, said it鈥檚 hard to say if the algae is becoming more prevalent, but outbreaks are being monitored.