NewsCalifornia News

Actions

Algae warning issued for California's San Luis Reservoir

Blue-green Algae (FILE)
Posted

SACRAMENTO, Calif. (AP) — California authorities issued a danger advisory for San Luis Reservoir in Merced County on Friday due to the toxin levels of blue-green algae in the water.

The Department of Water Resources said people should avoid contact with the water and avoid eating fish or shellfish from the lake.

Boating will be allowed but swimming and other water-contact recreation is not considered safe, the department said. Pets should also be kept away.

Blue-green algae, also known as cyanobacteria, can cause eye irritation, rashes, mouth ulcers, vomiting, diarrhea, and symptoms resembling colds and the flu.

The department said the algae conditions can change rapidly due to wind and wave actions that can move the bloom, which may accumulate to form mats, scum or foam.

The department noted that common water purification techniques such as camping filters, tablets and boiling do not remove the toxins.

The reservoir is about 45 miles (72 kilometers) southeast of San Jose in the hills of the western San Joaquin Valley. It is part of a state recreation area that is popular for fishing, boating, camping and picnicking.



Sign up for our Morning E-mail Newsletter to receive the latest headlines in your inbox.

,

Weather

Daily Forecast

View Hourly Forecast

Day

Conditions

HI / LO

Precip

Thursday

10/30/2025

Sunny

82° / 55°

2%

Friday

10/31/2025

Sunny

79° / 54°

3%

Saturday

11/01/2025

Sunny

79° / 55°

2%

Sunday

11/02/2025

Partly Cloudy

78° / 55°

2%

Monday

11/03/2025

Mostly Sunny

82° / 55°

0%

Tuesday

11/04/2025

Mostly Sunny

79° / 55°

0%

Wednesday

11/05/2025

Mostly Sunny

76° / 55°

5%

Thursday

11/06/2025

Partly Cloudy

72° / 53°

2%