Officials on Saturday were allowing the public to access the waters in the Alamitos Bay section of Long Beach, a week after a private sewage system failed and contaminated the popular recreation area.
A private sump pump that serves a residential community near the Cerritos Channel failed on Sunday, spilling sewage into the bay, city public health officials said.
Water tests conducted over two days by the city of Long Beach's Health Department showed bacteria levels to be safe, the city's chief health officer said on Saturday.
The closure initially included Mothers' Beach and other calm-water recreation areas, but not the ocean itself.
Officials expanded the closure by Tuesday to include all of Alamitos Bay because high levels of bacteria were detected.
The city said it is working to identify factors that contributed to the spill and is considering enforcement actions against the private property owner.