Toxic algae confirmed throughout Big Bear Lake: what residents and visitors need to know

State officials have confirmed harmful algal blooms throughout Big Bear Lake, visible as discolored water with a green sheen, floating scum, and clumps of algae^[1]. The blooms produce toxins potent enough to cause serious illness in people and animals — and for anyone planning a late-summer trip to the lake, that means keeping families and pets out of the water until conditions improve.

Marisa Van Dyke, a senior environmental scientist with the State Water Resources Control Board, explained to LAist that the blooms are caused by tiny bacteria that grow into large, flower patch-like formations across the lake's surface^[1]. "When you inadvertently swallow some of that water, it can contain those toxins," Van Dyke said. "It can be quite severe and cause you to need to have some hospitalization or even visit an animal veterinarian to get treatment."^[1]

What not to do — and what the blooms look like

The State Water Resources Control Board is urging people to avoid swimming in the lake, eating shellfish harvested from it, and drinking or cooking with lake water^[1]. Critically, boiling or filtering the water will not remove the toxins and will not make it safe^[1].

Van Dyke described the visual cues to watch for: "If [the water] looks a little bit more green … and there's a little bit more growth of something that looks kind of like a plant but not quite, there might be a harmful algal bloom occurring. So keep an eye on children and pets so that they don't get in contact with that material."^[1]

Children, dogs, and anglers face elevated risks

Dogs and children are especially vulnerable, according to the State Water Resources Control Board, because they are more likely to swallow water while playing and swimming^[1]. Pets should be kept out of the lake entirely and away from any scum or discolored water along the shoreline^[1].

For anglers who are already on the water, Van Dyke recommends rinsing fish thoroughly before handling them and eating only the fillets^[1]. If anyone does make contact with lake water, they should rinse themselves, family members, and pets with clean water immediately afterward, then dry off and change clothes as an added precaution^[1].

What we don't yet know

The current reporting comes from the State Water Resources Control Board. Big Bear News has not yet heard from the Big Bear Municipal Water District on whether drinking water drawn from the lake is affected, from San Bernardino County public health officials on any formal advisory or reported illnesses, or from local businesses — marinas, water-sports rentals, fishing guides — on how the bloom is affecting their operations. Those perspectives matter for the full picture, and Big Bear News is seeking comment from each.

In the meantime, residents and visitors can check current bloom conditions and advisories at the State Water Resources Control Board's harmful algal bloom portal at mywaterquality.ca.gov/habs.