The San Diego County Department of Environmental Health and Quality ordered beaches closed from the border to Carnation Avenue in Imperial Beach due to sewage from the Tijuana River.
The water contact closure was in effect Friday for the Tijuana Slough National Wildlife Refuge, Border Field State Park, and the city of Imperial Beach due to ocean water samples exceeding state health standards.
Closure signs will remain in place until water sampling results meet standards for recreational use.
Sewage flow from Tijuana has been a continuing problem, with a bi-national effort underway to improve wastewater treatment by the growing Mexican city.
Water conditions at San Diego County beaches can be checked online.