21 Aug 2014
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New Sewer Line Under Redwood Road Built to Last

CVSan has installed a modern sewer line under Redwood Road to improve the safety of the system and lower long-term maintenance costs. It is built to last 75 years!

New Sewer Line Under Redwood Road Built to Last


Drivers going south on Redwood Road over the Summer were working their way around the construction of a new sewer line. This project, the last bits of which will be finished in October, adds significant new capacity to our sewer system by adding a new 18” pipe running along Redwood Road from Heyer Ave. to Castro Valley Boulevard that will alleviate a bottleneck under Heyer Ave., reducing the risk of sewer overflows.

What is the new line’s job?

This new sewer line will gather wastewater flow from sewers running to Redwood Road under Heyer Ave. and down Redwood Road from the north. The new line will carry that wastewater to the new sewer under Castro Valley Blvd, which in turn will remove it from our community to the Oro Loma wastewater treatment plant. The most critical reason for the new, bigger sewer line is to alleviate a significant sewer overflow risk at the Heyer Avenue intersection during peak wet weather conditions.

There is an existing sewer line with a 6” to 8” diameter under the northbound lanes of Redwood road that was left in place and will continue to function. However, most of the wastewater will be diverted to the new 18” diameter line under the southbound lanes.

How long will this new line last?

This new sewer line on Redwood Road and Castro Valley Boulevard should last 75 years or more, and should not need any maintenance for 3-5 years, although we will place it on a full inspection schedule given this new line’s critical role in removing wastewater from our community. The benefits of the new line are:

  • Better protection against overflows during peak weather incidents.
  • Reducing maintenance costs for the Redwood Road sewer line and all the sewers that connect to it.

We estimate this could reduce maintenance costs for multiple pipes by as much as 92%, which is the financial reasoning behind the project.

Why will we save money over time?

An older pipe with multiple defects can require maintenance every three months. Assuming the new line on Redwood Road reduces the load on smaller pipes tied into it, the maintenance cycles for the smaller pipes can also be extended from three months to three years, saving a lot of money. The new line also benefits from the most modern design techniques, which improves prevention of environmentally costly sewer overflows.

What was done?

CVSan worked with Alameda County and Ghilotti Construction to install a new sewer sewer line; a 3,300 feet pipe running under the southbound side of Redwood Road. For most of that distance, the new line is vitrified clay pipe (VCP), with 70 feet of 16” diameter ductile iron pipe at the north end where Redwood Road and Heyer Ave intersect. VCP is the most durable material for a sewer line. We had to use ductile iron pipe for the critical crossing at Heyer and Redwood to prevent cross contamination with EBMUD’s fresh water pipes. The smaller cross section profile of the iron pipes also allows us to install the sewer line through smaller gaps under intersections where many other utilities cross. 

We also found issues with three existing sewer lateral lines when we opened the street to expose those pipes, and fixed them while connecting them to the new line. While these discoveries caused some delay, it was well worth fixing the problems we uncovered!

Questions? Call us!

We want all Castro Valley residents to understand what we are doing in the community, why we are doing it, and how it will affect the quality and price of your sewer services. Please contact us at 510-537-0757 with any questions or concerns you may have. You are also welcome to attend our regular Board of Directors meetings. Find the schedule here.

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