A sewer line blocked by grease caused 1,100 gallons of waste to flow through a storm drain, into Ballona Creek and out to the ocean on Sunday night, forcing partial closure of beaches within 100 yards of the creek’s mouth.

On Monday, the Los Angeles County Department of Public Health posted warnings to avoid contact with the water from the north end of Dockweiler Beach to the south end of Venice Beach, rain or shine.

“Due to the beach use advisory that was declared on Jan. 8, beach users should avoid water contact for at least 72 hours after the completion of this rain event,” Department of Public Health spokesman Bernard Tolliver said.

Los Angeles County changed the way sewage spills are reported in 2007 after then-L.A. County Supervisor Don Knabe called for an investigation of unreported discharges in the early 2000s. After the investigation, the number of reported spills increased 645% — from 11 in 2006 to 82 in 2007, according to a county audit report.

Recorded information on beach conditions is available 24 hours a day on the county’s beach closure hotline: (800) 525-5662.