MONTEREY (CBS SF) — Swimmers are being warned to stay out of the water at Monterey Municipal Beach after tests found high levels of bacteria, county health officials said Tuesday.

An advisory was posted after tests on water samples collected Monday found high levels of bacteria that could pose a risk of illness, according to the Monterey County Health Department.

READ MORE: Red Flag Warning Elevates Wildfire Fears Among Bay Area Residents

The bacteria can come from marine life and other animals, rainfall runoff and storm drains, or human activity, county health officials said.

READ MORE: One Dead, Three Wounded In Early Sunday Morning Shooting In Oakland's Uptown Neighborhood

ALSO READ: Three of the California’s dirtiest beaches are right here in the Bay Area. 

The advisory will be lifted when water samples show safe levels of indicator bacteria, health officials said. Those looking for more information can call (800) 347-6363 or go to www.mtyhd.org/beach.

MORE NEWS: VIDEO: Smash-and-Grab Suspects Arrested In Brazen Serramonte Center Jewelry Store Robbery

© Copyright 2015 by CBS San Francisco and Bay City News Service. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.