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B Basin (West Basin) Sewer Rehabilitation

Project Type: 

Collection System

Project Schedule/Status:

Construction will begin in April 2024 and is expected to be completed in Spring 2025.

Project Location:

B Basin includes downtown San Mateo, and areas West of El Camino Real between Highway 92 and Crystal Springs Road to the North (see map).

Where Will the Work Occur?

The work in Basin B will occur at multiple sites within the public right-of-way (ROW) and within easements on private property, including front yards, backyards, and driveways. Prior to the start of work, easement access notifications will be distributed to those residents whose property the contractor will need to enter. The contractor will provide additional notices two to three days prior to work starting in specific areas of B Basin. The homepage provides an interactive map  where you can type in your address to see if there are any nearby construction areas.

Project Description:

The purpose of the B Basin Sewer Rehabilitation project is to upgrade and rehabilitate aging pipes and manhole covers. Cracked sewer pipes and laterals allow outside rainwater and groundwater to flow into the sewer system. Faulty manhole covers also allow outside water into the system. Improvements are needed to ensure proper operation, repair leaks to meet regulatory requirements, and prevent high flows that can result in sewer overflows.

A condition assessment was the first step toward finding cost-effective and technically-feasible fixes to minimize inflow and infiltration (I/I). Closed-Circuit Television (CCTV) studies were conducted using a remote-controlled camera. The information was analyzed to identify problem areas in the collection system and to design spot repairs without the expensive guesswork associated with digging blind.

The two types of repairs this project will address are:

  • Gravity Sewer System – Spot and Segment repairs
  • Manholes – Repairs and replacements

Map of B Basin

Gravity Sewer Spot Repairs and Replacement

Gravity mains offer reliable movement of sewage and surface runoff through a sewer system. However, over time the ground can shift, roots can penetrate, and traffic can impact sewers causing them to settle and crack. During this project, our contractors will spot repair damaged or displaced existing 6-inch, 8-inch, 10-inch and 12-inch gravity sanitary sewer pipe with new polyvinyl chloride (PVC) sewer pipe throughout B Basin.

Manhole Repair and Replacement

Manholes need to be easily accessible for sewer maintenance and related emergencies. Over time, manholes can become covered with grass or can sink below the grade level of lawns, roads, or sidewalks. There are several methods of rehabilitating manholes, and the method selected for a job depends on the condition of the manhole. Common rehabilitation methods used for projects such as this include:

  1. Replacing the frame and cover;
  2. Applying cement mortar as a binding agent to the inside; and
  3. Applying epoxy liner to the inside for resurfacing.

Engineer Firm Name and Key Project Contact: 

Engineer Consultant: Harris & Associates, Kourosh Iranpour,
Construction Manager: Townsend Management, Inc., Dana Perry (415) 218-3867 or, Tolio Ybarra (415) 254-2208 or
Contractor: Westland Contractors Inc., Neil Hunt (510) 842-3663 or
City/CWP Project Manager: Laura Webb, 650-522-7322,