San Diego, California, USA

South Bay Wastewater Plant San Diego,California

Status: Completed construction


The City of San Diego Water Department provides water service to residents of the city from its three existing water treatment plants. Ninety percent of the city’s raw water supply is imported, mainly from the Colorado River. This dependence on external sources of supply has led to high water costs and increased conservation efforts, including water reuse projects.

Wastewater treatment is provided by the San Diego Metropolitan Wastewater Department, which services both the city and a number of participating agencies located outside the city limits. Wastewater generated in the southern region of San Diego is currently being
conveyed to the Point Loma Wastewater Treatment Plant for treatment via the South Metro Interceptor. The South Metro Interceptor is the major sewer pipeline serving the South Bay community in San Diego, and was constructed in the early 1960s. The interceptor is beginning to deteriorate and is currently operating near full capacity.

As part of its US$1.5 billion capital improvement program, the Metropolitan Wastewater Department proposed the construction of the South Bay Water Reclamation Plant.


The South Bay Water Reclamation Plant consists of secondary and tertiary treatment facilities, an operations and maintenance building, a chemical building and parking areas. The proposed treatment process includes influent screening, grit removal, primary sedimentation, primary flow equalization, activated sludge processes, secondary sedimentation, coagulation, filtration, and ultraviolet light disinfection.

The Plant will provide an average of seven million gallons per day (mgd) of advanced wastewater treatment capacity and reclaimed water for reuse, reducing demand for scarce raw water supplies. The plant is designed to allow future expansion to an average of 14 mgd treatment capacity.

Reclaimed water produced by the plant will be conveyed through reclaimed water distribution pipelines to reuse markets in the South Bay area. Excess effluent from the plant that cannot be reused will be conveyed through the South Bay Ocean Outfall to the ocean for final


In addition to the environmental benefits provided by reclaimed water, construction of the new plant will provide capacity relief for the South Metro Interceptor by diverting flows normally conveyed to the Point Loma Plant to the new facility for treatment, which will reduce the potential for sewer spills. The plant will also result in substantial cost savings for all system ratepayers by allowing the City to forego construction of secondary treatment capacity throughout the MWWD’s service area, in accordance with an agreement with the U.S. Environmental Protection Agency.

Project Financing

Total Project Cost US 99.59M
NADB Funding US 17.21M - NADB Grant: BEIF
Other Funding Partners Border Environment Infrastructure Fund
City of San Diego, California
U. S Environment Protection Agency