Residents are being asked to avoid Coronado and South Bay ocean water until otherwise notified after record-breaking rainfall left many county beaches with contaminated water.
Saturday's rainfall broke records in at least 11 locations, including five places that had the most rain ever recorded on any day in July, according to the National Weather Service.
In San Diego County, rain totals shattered records set 113 years ago, NBC 7 Meteorologist Jodi Kodesh said.
Following that rain, the County of San Diego Department of Environmental Health issued water contact closure areas along San Diego shores due to sewage runoff leaking into ocean water.
Sunday evening, county officials said the Tijuana Slough National Wildlife Refuge and Border Field State Park had both been closed due to sewage-contaminated flow from the Tijuana River. The coastline closed goes from Seacoast Drive to the International Border.
On Monday, officials expanded that existing closure to Imperial Beach, Silver Strand State Beach shorelines and all shorelines north of those to including Coronado.
A beach hazards statement at county beaches is in effect through Monday evening for potential lightning, strong rip currents and high surf with sets hitting five to seven feet.
Warning signs will remain in place until ocean water is safe for recreational use, officials said.
For more information on beach closures, click here.