The Los Angeles County Sanitation Districts Clearwater project that will replace a pair of aging wastewater tunnels in Los Angeles, CA with an 11-km (7-mile) long precast concrete tunnel got a financial boost of $441 million from the U.S. Environmental Protection Agency (EPA).

EPA is providing a Water Infrastructure Finance and Innovation Act (WIFIA) loan to the Los Angeles County Sanitation Districts for the clearwater project.

The 5.4-m (18-ft) diameter tunnel will carry treated water from the joint water pollution control plant in Carson, CA, to ocean outfalls in L.A.’s San Pedro neighborhood. The new tunnel will have a greater capacity for high flows than the existing tunnels, which were built in 1937 and 1958, ENR reported.

County sanitation districts officials say major storms almost pushed the tunnels past their capacity twice. Those aging tunnels also cross two earthquake faults, but do not meet modern seismic standards. If the capacity is exceeded or the tunnels fail, sewage may discharge into surrounding waterways. After the completion of the new tunnel, the two existing tunnels will be used as backups.

The project has been in the works for several years. Design work with tunneling experts from engineering firms Parsons Corporation and McMillen Jacobs Associates plus geotechnical firm Fugro Consultants completed in 2018. In 2019, the sanitation districts awarded a $630-million contract to Dragados USA Inc. for the project. Tunneling began in 2021. Officials expect work to complete in 2027.

WIFIA loans are low-cost and long-term, given for significant water infrastructure projects. EPA says Los Angeles County will save about $76 million by financing with the WIFIA loan.

“This loan will help us build infrastructure that is critical for the region and minimize the financial impact on our ratepayers,” Robert Ferrante, chief engineer and general manager of the sanitation districts, said in a statement.

EPA is financing more than $31 billion in water infrastructure upgrades with WIFIA loans, according to the agency. On May 9, EPA also announced that it would provide $65 million in loans for two projects that will increase groundwater treatment capacity in Multnomah County, OR.