Those heading to the beach this week are advised to stay out of the water as all Los Angeles County beaches are under advisory for excessive bacteria from rainfall.

The advisory is in effect starting Tuesday and will remain until Friday, Dec. 30 at 4:30 p.m.

The public is advised to stay out of the water due to heightened levels of “chemicals, debris, trash, and other public health hazards from city streets and mountain areas likely to contaminate ocean waters at and around discharging storm drains, creeks, and rivers,” said the Los Angeles County Department of Public Health.

People who enter the ocean water during this period could become ill, officials warned. Those especially at risk include people with weakened immune systems, children and the elderly.

The Department of Public Health recommends beachgoers avoid contact with ocean water for at least three days after significant rainfall.

The current advisory for L.A. County beaches could be extended depending on further rain activity, officials said.

Rainfall arrived in the L.A. area on Tuesday afternoon, with periods of brief heavy rain expected to continue off and on through Friday, according to the National Weather Service.

Surfers should avoid ocean waters in L.A. and Ventura counties due to high surf and rip currents. Drowning risk will increase during this time as rip currents can pull swimmers out to sea and waves can wash people off beaches and rocks, and capsize small boats.

Read the latest updates and beach advisories from the L.A. County Department of Public Health on their website.