Health officials have lifted the water contact closure order for the Tijuana Slough National Wildlife Refuge, Border Field State Park and the Imperial Beach shorelines after a bacteria issue.
Beaches from the International Border through Carnation Avenue have now been declared safe.
On Aug. 8, the San Diego County Department of Environmental Health and Quality issued the closures after testing showed ocean water samples exceeding state health standards for bacteria.
The Tijuana River enters San Diego County from Mexico and flows through the southernmost part of the county before emptying into the Pacific Ocean.
Sewage-contaminated runoff that enters the river in Mexico often moves north along the San Diego County shoreline.
Beaches in southern San Diego County have been closed off and on all year.