Fourth St. 84-in Interceptor Phase VI-A (Fourth St Sewer)

Project Updates:

November 3, 2021

Fourth St is now open for southbound through traffic.

Northbound traffic on Fourth St and eastbound traffic on Commercial St remain closed through Fall 2021. These closures are necessary for pipe installation, temporary sewer bypass, utilities connections, and dewatering well construction.


  • No turns from Fourth St to Commercial St.

  • Right turns only from Firth St to Commercial St.

  • Traffic control will be in place.

  • At least one driveway access will be maintained for each property.

  • Detours will be in place to route drivers around the area of work.

  • No Parking signs will be posted and parking will be restricted.

  • Temporary sewer service interruptions, which will be coordinated with affected services ahead of time.



General Project Information:

The Fourth St Sewer project will improve the capacity of the City's sewage system by replacing 48-inch and 54-inch diameter sanitary sewer pipes with 4,500 feet of 84-inch diameter pipes along North street and approximately 300 feet of 72-inch diameter pipes along Commercial Street.

Fourth St is a busy San Jose roadway, with fronting residences and businesses, which will require extensive community outreach and complex traffic management. The project will cross under US 101, I-880, several large storm pipes and existing utilities, requiring permits to perform work within Caltrans' right of way.

The project will allow:

  • future shutdown and maintenance of City sewage systems

  • future decommissioning of deteriorated 60-inch brick sewer that runs parallel to Fourth Street, which was built in the 1890's

  • sewage flow from Commercial St to Old Bayshore Rd north of US 101

  • installation of a small diameter local collector sanitary sewer system

Project Map:




Construction Begins

Summer 2019

Tunneling Work (Under US 101)


Fourth St Pipe Replacement

Fall 2019 – Summer 2021

Pipe Laying Work (Under I-880)

Fall 2020 – Spring 2021

Commercial St Pipe Replacement

Winter 2021 – Fall 2021


Spring 2021 – Fall 2021

Project Completion

Fall 2021

Construction Hours:

Construction will take place Monday through Friday, 7:00am to 5:30pm. No work is anticipated on weekends, unless warranted. All construction dates and times are subject to change due to weather and unforeseen conditions.

Anticipated Project Impacts:

  • Shutdown of 1/4 City interceptors for maintenance/repair

  • Traffic will be temporarily impacted during construction along North Fourth Street

Construction Notice Archive:

Construction Update - October 2021

Construction Update - April 2021

Construction Update - August 2020

Construction Update - May 2020

Construction Update - November 25, 2019

Construction Update - November 8, 2019

Contact Information:

Project Email:

Project Info Line:

(888) 778-8453

24hr Emergency Line:

(408) 767-6362


Project Fact Sheet:



Fourth St Sewer construction activities will continue as planned due to an exemption for public works construction in the Santa Clara County Health Officer shelter-in-place order. The City of San Jose has evaluated all existing construction projects and has designated the Fourth Street project as an Essential Governmental Function authorized to continue construction pursuant to Section 13.f.v.4 of the March 31, 2020 Health Officer order.

For more information about ongoing projects, please visit the Capital Project Management System website.