San Francisco Public Utilities Commission
Skip to page body Home Customer Service How To Environment Projects & Programs About Us


Seismic Upgrade of BDPL Nos. 3 & 4 (WSIP)

Project Update
Project Video: BDPL Nos. 3&4 Seismic Upgrade in Fremont

How do you replace two regional water pipelines that run directly underneath a major traffic corridor and along a major earthquake fault? This is the challenge for our engineering and construction team at the intersection of Mission Blvd. and I-680 in Fremont.

In order to accomplish this engineering feat, the SFPUC and general contractor Steve P. Rados are working beneath the roads to install a unique system of pipes, joints and vaults which will ensure delivery of water after a major earthquake.

Throughout construction, the contractor will employ best management practices to control noise, dust and other disturbances around the site. As of March 2015, the temporary on-ramp developed for construction is in the process of being dismantled in order to restore the I-680/Mission Blvd. interchange to its original alignment, one of the final phases in the construction process. Final completion for this project is anticipated for May 2015.

Follow us on Twitter: @I680H2OPipeWork

If you have questions or concerns, please call our 24-hour answering service at 866-973-1476 or follow our construction blog.

      Workers install a pipe tie-in at night to avoid slowing traffic during the day.

Project Description
Seismic Upgrade of BDPL Nos. 3 & 4 at Hayward Fault cross the intersection of Mission Boulevard and Interstate 680 (I-680) in Fremont. The pipelines cross three traces of the fault in this area, and it is very likely that an earthquake on the Hayward Fault would rupture one or both of these pipelines. To avoid major damage to this essential part of the Bay Area’s water-delivery system, this project will replace the existing BDPL No. 3 with a new pipeline between two recently installed vaults on either side of the Hayward Fault. The new pipeline will be highly reliable in the event of a major earthquake. The existing BDPL No. 4 will be seismically retrofitted at the three fault traces. All construction activities will take place in the SFPUC’s existing right of way and in staging areas as indicated on the map at the bottom of this page. The project will primarily consist of:

BDPL No. 3 Improvements

  • A new 300-foot-long concrete vault will be constructed under Mission Boulevard near the I-680 interchange. Installation of a new 300-foot segment of 72-inch-diameter, welded-steel pipeline in vault. New 72-inch-diameter ball joints and slip joints.
  • About 400 feet of 78-inch-diameter welded-steel pipe will be installed in an existing, unused casing pipe at the crossing under I-680.
  • About 1,450 feet of new, 78-inch-diameter welded-steel pipe will connect the existing and new pipe segments between the two vaults.
  • The existing BDPL No. 3 will be abandoned in place, but modifications will be made to it to collect and divert water from the area and prevent the undermining of the new BDPL No. 3.

BDPL No. 4 Improvements

  • At Hayward Fault Trace C, about 400 feet of BDPL No. 4 will be replaced with new steel pipe.
  • BDPL No. 4 will be encased with concrete outside the existing slip-joint vault at Hayward Fault Trace B.
  • At Hayward Fault Trace A, about 300 feet of BDPL No. 4 will be slip-lined with a new steel pipe, and an expansion joint will be installed in a new vault south of I-680.
  • Modifications to the existing slip-joint vault will be made, including enlarging BDPL No. 4 pipe penetrations in the vault and adding new drainage systems and new roof panels.
Sample design of ball joint Proposed project area map

Sample design of ball joint

Project work area.


Project Information

    September 2012
    September 2015
  • COST
    $75 Million

Additional Information

The information shown reflects the current forecast information published in the latest WSIP Quarterly Report.



Need More Information? Contact

Email: or
24-Hour Answering Service: (866) 973-1476

Sign Up for Our E-mail List


Seismic Upgrade of BDPL 3 & 4 Blog