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Basin 1b Pipe Capacity Improvements

Map of project location.Project Type: 

Collection System

Construction Start & End Dates:

Construction began in May 2019 and was completed in February 2020

Project Location:

The work was completed in two areas:

Area One:

  • Edinburgh Street from Fordham Drive to Sonora Drive
  • Sonora Drive from Edinburgh Street to Maple Street
  • Maple Street from Sonora Drive to Hobart Avenue
  • Hobart Avenue from Maple Street to Palm Avenue
  • Palm Avenue from 12th Avenue to 16th Avenue
  • 16th Avenue from Palm Avenue to 80 feet northeast of South B Street
  • Barneson Avenue, 20 feet southwest of El Camino Real

Area Two:

  • 5th Avenue from El Camino Real to 90 feet northeast of S Railroad Avenue
  • 9th Avenue from El Camino Real to Palm Avenue
  • San Mateo Drive from East 4th Avenue to East 5th Avenue
  • Alley between East 4th Avenue and East 5th Avenue from El Camino Real to San Mateo Drive

Project Description:

The work was completed to increase the integrity of the sewer system, reduce sewer overflows during storms, and help the City meet regulatory requirements. The project areas were selected using hydraulic modeling to determine the most efficient, cost-effective solutions.

Basin 1b, located in the central portion of San Mateo, consisted of work in two different areas. Most of the work took place from Edinburgh Street to 16th Avenue, as shown on the map. Orange shows where existing sewers were replaced and upsized (2,935 feet), while green and yellow show the new relief sewer lines (3,260 feet). A short, 10-foot span of new pipe under Barneson Avenue was also installed.

The rest of the project (shown in blue) included rehabilitation and replacement work in downtown San Mateo on San Mateo Avenue, the alley between East 4th and East 5th Avenues (between San Mateo Drive and El Camino Real), and 9th Avenue between El Camino Real and Palm Avenue. The total length of repaired, rehabilitated, and upsized pipe is 9,340 feet.

The City’s construction contractor completed the work three months ahead of schedule.

Key Project Contact:

Sarah Pham, Project Engineer, 650.727.6884 or