The De Soto Trunk Line is a large pipeline used to transport water to residents and businesses in the San Fernando Valley communities of Chatsworth, Canoga Park and Winnetka. The trunk line was originally placed in service in 1917 and is a riveted steel pipe ranging from 24 to 52 inches in diameter.

Trunk lines provide the transmission capacity to move large amounts of water from tanks and reservoirs to distribution mainline pipes throughout the city. West valley trunk lines are aging, deteriorating, and nearing the end of their service life. To ensure customers can count on delivery of safe, reliable water, LADWP has a water infrastructure improvement program that includes projects to replace or upgrade major system components that are old or located in seismic areas.

Project Description

The 102-year old De Soto Trunk Line will be replaced with 48-inch and 54-inch earthquake resistant pipeline along Devonshire Street, Mason Avenue and Roscoe Boulevard.

Once installed, the new three and three-quarter miles of trunk line will connect with the existing De Soto Trunk Line at Devonshire Street and Roscoe Boulevard. The existing De Soto Trunk Line will then be taken out of service.

The project also includes approximately 850 feet of 36-inch and 42-inch earthquake resistant pipeline replacement at the intersection of De Soto Avenue and Victory Avenue.

The upgraded pipeline will increase the safety, capacity, and reliability of LADWP’s water system in the western San Fernando Valley. The proposed project will also include installation of maintenance access holes, valves, and flow meters that are required for operating, monitoring, and maintaining the trunk lines.

Environmental Documentation

Following guidelines outlined in the California Environmental Quality Act (CEQA), LADWP has prepared an initial study to analyze the potential environmental impacts of the project. The original Mitigated Negative Declaration (MND) was circulated for public review and comment in November 2018. Given the changes in the design of the project, a revised MND was circulated from March 26, 2020 through April 27, 2020 and was approved by LADWP’s Board of Commissioners on July 28, 2020.

For environmental documents related to this project, go to:

Construction Information

  • Tentative: January 2025 – July 2029

Contact Us

Project Manager  
Eric Kim  
[email protected]

Community Liaison  
Christina Holland  
[email protected]