Joint Intercepting Sewer Rehabilitation – Phase One

Project typeSystem Improvements
Project value$9 million

Joint Intercepting Sewer temporary pipes_low res.jpg

Project Overview

The Joint Intercepting Sewer (JIS) is an underground pipe approximately 9,000 feet long that conveys raw sewage from Mountain View, Los Altos, Los Altos Hills, and a portion of Palo Alto’s sewershed areas. Collectively, these flows contribute to more than half of the influent at the Regional Water Quality Control Plant.

The JIS was constructed in 1972 of reinforced concrete pipe sections that are 72-inch in diameter. The final leg of the JIS pipeline, which runs along the trail on the western edge of Byxbee Park to the Plant, is severely deteriorated and in need of repair.

Phase 1 of this project will rehabilitate approximately 2,375 feet of the JIS pipe sections by installing a structural liner onto the interior surfaces of the pipe. The new liner will resist corrosive sewer gasses, extend the life of the pipeline, and protect the pipe from structural failure.

The upstream pipe sections (approximately 6,600 feet to the metering station at 1151 San Antonio Road) show less severe deterioration and will be reassessed in the next five to ten years to establish the timing and need for Phase 2 rehabilitation work.

This project was identified in the Long-Range Facility Plan (LRFP) which was completed in 2012.

Scope of Work

Install temporary fencing to isolate and secure the construction area
Install a temporary sewer bypass pumping system to divert sewage and allow access into the sewer pipe that needs rehabilitation
Remove debris and clean the pipe. Inspect and repair the pipe to stop infiltration, if any
Install a structural liner onto the interior surfaces of the existing concrete pipe
Rehabilitate existing maintenance holes (access structures) by applying corrosion protective coating
Restore work areas

Public Impact

To protect the public from construction activities, a section of the trail on the western edge of Byxbee Park Hills will be closed between 3/3/2025 and 11/30/2025. The construction area will be fenced off with six- to eight-inch gaps at the bottom to allow wildlife to pass through. Trail detour signs are posted at the park. When construction vehicles are active in the area, traffic control flaggers will be present to protect and advise park users on detour routes.

On the map below:

Red lines show the sections of the trail that will be temporarily closed between 3/3/2025 and 11/30/2025.
Yellow lines show the detour routes.
Purple square and circle are the locations where signage will be posted.

Trail Detour Signage for JIS

Starting in June 2025, hikers may notice trucks set up to perform the pipeline repair. The long set up is called a "train" and will be located behind the construction fence in Byxbee Park, near the landfill offices. Learn more and see photos:

Resin Impregnation Process Description.pdf(PDF, 18MB)