RANCHO MURIETA, CA (MPG) - The Rancho Murieta Community Services District posted an Aug. 5 notice on its website warning residents about the discovery of cyanobacteria – blue-green algae – in Clementia Reservoir.

Humans and pets can be exposed to harmful algae blooms through accidental ingestion while swimming, by inhaling water spray aerosols during water recreation such as boating, or by being in the water where a bloom is occurring.

Although swimming and direct reservoir contact are allowed at Clementia Reservoir, the district is advising residents to avoid water where a visible blue-green algae bloom is present. The district also plans to have the reservoir treated as soon as possible to prevent the expansion of the cyanobacteria and protect the water supply, the notice said.

“Your best bet is – ‘When in doubt, best keep out,’” the notice said.

In September 2023, after blue-green algae was found in Chesbro Reservoir, the district contracted with Solitude Lake Management to treat the affected section with a low dose of copper sulfate algaecide.