Editor’s note: This story was updated to reflect the correct areas under the advisory. The Silver Strand is the only portion of Coronado under advisory.

SAN DIEGO — A boil water advisory originally in effect for residents in Imperial Beach and Coronado’s Silver Strand on Thursday has now been expanded to portions of San Diego and Chula Vista, local water officials said.

Residents are urged to boil their water before using it or use bottled water after E. coli bacteria was found in the drinking water system.

You can see an updated map showing the areas under the advisory below or zoom in on the impacted areas here. The map was updated by American Water Works around 9:15 a.m. Friday.

A map of areas under a boil water advisory. (American Water Works Service Company, Inc.)

The State Water Resources Control Board Division of Drinking Water initially issued a boil water advisory for Imperial Beach and Coronado’s Silver Strand Thursday afternoon, according to the County of San Diego’s emergency website. On the Silver Strand, the advisory is only in effect for areas south of Fiddler’s Cove, the Coronado Police Department said. Around 8 p.m., American Water Works expanded the advisory to portions of San Diego and Chula Vista.

The order is in effect until lab results confirm there is no bacteria in the water supply, but according to American Water Works, the boil water advisory is expected to last through Sunday at 11 a.m.

“The presence of E. coli bacteria indicates that the water may be contaminated with human or animal waste,” the county said.

Nearby areas covered by the Sweetwater Authority and Otay Water District are not impacted by the boil water advisory.

The advisory states the water is not safe to drink and should be boiled for three minutes to kill bacteria. Residents are also encouraged to use bottled water for drinking, brushing teeth and cooking.

E. coli infection can lead to diarrhea, cramps, nausea and headaches. Infants, young children, some elderly and people with severely compromised immune systems are especially at risk.

“Our air is polluted, our ocean is polluted and now our drinking water is polluted,” said Paloma Aguirre, the mayor of Imperial Beach.

Officials are calling for more help in curbing the sewage flows that swamp the community’s beaches every time it rains. Mexico’s sewage system washes all of their waste through the Tijuana River Valley, polluting the ground water and ocean.

When Tropical Storm Hilary hit, the mayor says billions of gallons of toxic waste flowed north into her city.

“It was a tsunami of sewage, of trash and tires,” Aguirre said.

State and county regulators are investigating where its water system was contaminated. 

Pallets of water cases are being handed out at the corner of Palm Avenue and 10th Street in Imperial Beach. The California American Water company will start handing out cases of water to residents of Imperial Beach at 9 a.m. Friday.

FOX 5’s Jaime Chambers, Domenick Candelieri and Sir Milo Loftin contributed to this story.