Lynn Valley trunk sewer upgrade


We are replacing the trunk sewer on Mountain Highway between East 24th Street and East 18th Street.

Built in 1964, the aging sewer has reached the end of its service life. The new sewer will be constructed with larger pipe to increase capacity to meet current and future demands. This significant piece of infrastructure is responsible for carrying sanitary waste for approximately 21,000 area residents.

Construction is scheduled to begin in fall 2022 and will take approximately one year to complete.  

Crews will use micro-tunnel construction to excavate an underground tunnel without disturbing the road above. This method will have less impact on traffic than traditional excavation methods. See the 'micro-tunnelling' tab below for more.

News & updates

December 22, 2023 — Project completion

The project is now in the closing phase, with the new sewer fully operational. East 24th at Mountain Highway has now been reopened. The remaining work is limited to removing the site compound and reinstating the area. 

November 17, 2023 — East 20th Street reopened 

The intersection of Mountain Highway and East 20th Street has been reopened to all traffic. Crews continue work along Mountain Highway and East 24th Street. 

November 6, 2023 — Sewer connection is complete

The new Lynn Valley Trunk Sewer has now been connected to the existing system and is fully operational. Tie-ins to the new developments on Emery Place are now being completed and the road is being reinstated, with East 20th expected to reopen in the coming weeks and East 24th reopen by the end of the year.

October 18, 2023 — Bypass pumps to run 24/7 starting Friday

Starting Friday, October 20 and lasting for about a week, crews will run a bypass pump and generators 24/7 while the new sewer is connected to the existing system. The pumps will be located at East 24th/Emery Place and Mountain Highway.

Since completing the underground tunnel boring work at the end of August, the team has worked hard to prepare the tunnel for commissioning, including grouting each of the joints between the tunnel sections and installing the manholes at the launch shaft and reception shaft. This work has gone well and is nearing completion. The tunnel is currently being tested and the team are preparing to connect the new sewer to the existing system.

The bypass pumps are now required to be run 24/7 to manage existing flows while the manholes are constructed and the new sewer is connected. Construction of the manholes will occur during regular working daytime hours. Work will be permitted on Sunday to minimize the duration of the bypass. 

After the sewer is operational, the remaining work will be to reinstate the work area and restore Mountain Highway to normal traffic operations. 

August 31, 2023  — Tunnel Complete

A major milestone in this project has now been reached. The tunnel boring machine has reached the reception shaft at East 24th St., completing the tunneling works.

However, there is still much to be done. The remainder of the work involves decommissioning the tunneling equipment, installing manholes at the launch and reception shaft, installing additional manholes to tie in the new sewer to the existing system and testing/commissioning the tunnel. Once that work is complete, the construction sites at East 20th and East 24th will be dismantled and the road reinstated. The project is expected to be completed in late fall. 

August 3, 2023 — Additional night work required for one week

To allow road work on the narrow section of Mountain Highway between East 24th Street and St. Stephens Place, there will be single-lane alternating traffic on Mountain Highway and overnight work between 8pm and 6am for approximately one week, starting August 14. This overnight work is required to maintain regular two-way traffic throughout the day.

The weekly overnight maintenance work will also continue for approximately one to two nights per week until September, as outlined below.

July 11, 2023 — Night work

For approximately two nights per week starting next week and continuing through September, continuous overnight work may be required to conduct routine maintenance of the tunnel boring machine. This work will necessitate use of the site generator, groundwater pumps, a construction crane and other construction tools. All efforts will be taken to minimize the disturbance to nearby residents. 

June 27, 2023 — Northbound tunnel boring commenced

Last week, crews re-installed the tunnel boring equipment into the entry shaft at East 20th Street and began boring the northbound tunnel. As with the southward run, sections of sewer pipe will be installed as the tunnel is bored under Mountain Highway to East 24th Street. 

June 6, 2023 — Next steps

Within the next week, crews will begin preparations between East 20th and East 24th Streets for the northbound run of the tunnel boring. 

June 1, 2023 — Southbound tunnel complete

Today, a major milestone was completed in the project as tunneling crews reached the southbound terminus, completing the installation of new sewer pipe sections between East 20th and East 18th Street. The tunnel boring machine has been lifted and moved back to East 20th Street where it will be refit to prepare for the northbound run to East 24th Street.

May 17, 2023 — Construction and tunnel update

Tunnelling crews continue to make steady progress southward under Mountain Highway to East 18th Street. Once the boring equipment arrives at East 18th Street, and the sections of new sewer pipe are installed, the tunnel boring machine will be removed and placed back at East 20th to commence the northward leg of the tunnel. 

May 10, 2023 — Tunnelling progress

Crews working the micro-tunnelling equipment have reached the halfway point to 18th Street. Progress to date has been somewhat slowed by some large granite boulders, but crews hope to make up time in the second half of the run. 

April 21, 2023 — East 24th Street to be closed from Mountain Highway

Starting Thursday, April 27, access to and from East 24th Street at Mountain Highway will be closed to facilitate utility work and construction of the exit shaft. This closure is expected to remain in effect for the duration of the project in fall 2023. Access to the 1300 block of East 24th Street and Hazellynn Place will be from Viewlynn Drive and will be limited to local traffic only. 

April 17, 2023 — Tunnel boring progress

The micro-tunnel boring work has begun and has progressed on schedule in a southbound direction towards it's destination at East 18th Street. Meanwhile, crews have been busy at the 18th Street intersection in preparation of work to construct the reception shaft and ultimately connect the new pipe to the existing sanitary sewer. East 18th Street will remain open during construction and a minimum one lane in each direction will remain open on Mountain Highway. Drivers are reminded to use caution and please drive slowly through the work area. 

March 29, 2023 — Installation of tunnel boring machine

The micro-tunnel boring machine has been lowered and installed, and crews are preparing to begin the tunneling work under Mountain Highway starting this week. Materials from the tunnel boring process will be sorted in the separation facility temporarily set up on Mountain Highway, where a noise barrier has been installed to minimize disruption to the community. 

Crews will also commence road work at East 18th and Mountain Highway, where the exit shaft for the tunnel will be constructed. Road widening work in this area will help to maintain two-way traffic through the site, with a goal to minimize traffic delays. 

Installed micro tunnel boring machine

March 7, 2023 — Completion of launch shaft at East 20th

The launch shaft construction will soon be complete, and we anticipate the delivery of the tunnel boring machine in the coming weeks. Shortly after, tunnel excavation work will begin underground along Mountain Highway, starting in the southbound direction toward E 18th Street. 

January 23, 2023 — Construction begins

Construction of the launch shaft for the micro-tunneling boring machine has started at the intersection of Mountain Highway and 20th Street. Here, a large circular shaft will be excavated to a depth of 10 metres.

Over the next month, once the shaft is completed and the boring equipment is in place, tunneling underneath Mountain Highway will first begin in a southward direction, towards 18th Street, where an exit shaft will be constructed. The intersection at 18th will remain open, however traffic will be one lane in each direction. In the coming weeks, a facility will be installed on the west side of Mountain Highway to separate the rocks, soil, and water left behind by the tunneling process. 

Yellow excavators begin digging a hole for a trunk sewer project.

December 19, 2022 — East 20th closure extended due to weather

Winter weather conditions are preventing the patch and repave of the intersection following watermain relocation. Unfortunately, this means that the closure of East 20th Street at Mountain Highway will not be able to reopen over the Christmas break, as previously planned. The closure will now remain in place for the duration of the project. 

December 5, 2022 — Work rescheduled

Watermain relocation work and related street closures that were postponed this week have been rescheduled to start Monday, December 12 and finish by December 21, 2022. This work requires the closure of East 20th Street at Mountain Highway. In addition, traffic on Mountain Highway will be reduced to one lane northbound at East 20th.

After the watermain work is complete, East 20th Street will reopen for the Christmas break on December 22 and close again on January 9, 2023 for the remainder of the project. 

December 2, 2022 — Closure postponed

The watermain work and related closures that were scheduled to start on Monday, December 5 have been postponed. We will provide an update as soon as this work is rescheduled. 

November 29, 2022 — Closure of East 20th Street

Starting Monday, December 5, East 20th Street at Mountain Highway will be closed to all traffic for the duration of the Lynn Valley trunk sewer project through summer 2023.

Also starting Monday, traffic on Mountain Highway at East 20th St. will be reduced to one lane northbound for approximately two weeks to relocate a watermain in preparation for the micro-tunnelling. One lane will remain for southbound traffic. Following this phase of work, all traffic lanes will be restored temporarily until January 2023, when the micro-tunnelling work will begin.

One lane in each direction will be maintained on Mountain Highway for the duration of the project.

October 27, 2022 — Site preparations 

The contractor will be setting up on site starting next week, and beginning preparations for the micro-tunnelling work to follow. 

Map of construction area

Construction area

This map shows the sewer trunk construction area along Mountain Highway. One lane of traffic will be maintained in each direction on Mountain Highway.

East 20th Street will be closed at Mountain Highway to all vehicle traffic for the duration of the project, starting December 5, 2022. Starting later this spring, East 24th Street will also be closed to traffic at Mountain Highway until the project is completed in fall 2023. Pedestrian access will be maintained at all times. For your safety, please obey all traffic signage and flaggers in the area. 

A map showing construction areas and road closures for the Lynn Valley Trunk Sewer Project, between E 24th St and E 20th St. Later this spring E 24th closed to vehicles at Mountain Hwy. E 20th closed to vehicles at Mountain Hwy.

Construction timeline

Southbound boring begins Spring 2023

We expect tunnel boring work will begin underground along Mountain Highway in late March or early April, starting first in the southbound direction. As the tunnel works its way towards its destination at East 18th Street, sections of the new sewer pipe will be installed along the way. Construction will begin shortly at East 18th Street to build the reception shaft and manholes where we will ultimately connect the new pipe sections to the existing sewer.

Heading north 

Once the new sewer between East 20th Street and East 18th Street is installed, the tunnel boring machine will be returned to the shaft at East 20th Street and relaunched in the northbound direction to East 24th Street. Construction of the reception shaft at East 24th Street will begin later this spring and will require the closure of East 24th Street at Mountain Highway for the remainder of the project. 

*Timeline at glance:

  • March – Tunnel equipment installation and setup
  • March to April – Tunnelling from East 20th St to East 18th St
  • Early April – Set up construction at East 18th St
  • May to June – Tunneling from East 20th St to East 24th St
  • Mid-May – Set up construction at East 24th St
  • August – Reinstatement at East 18 St
  • Sept/Oct – Finishing work inside the tunnel and demobilization of tunneling equipment
  • October – Decommissioning of launch and receptions shafts, and installation of manholes
  • Oct/Nov – Commissioning of tunnel and tie in to existing system
  • Nov/Dec – Reinstatement of site (subject to weather conditions)

*Please note, this timeline is subject to change. 

Micro-tunnelling: what to expect

Micro-tunnelling: A less disruptive method of construction

Traditional construction methods would require trenching the entire stretch of Mountain Highway to complete this project.

Instead, we will use micro-tunnelling methods that utilize a boring machine to excavate an underground tunnel. This method will only require three excavations along the entire sewer route: one for the entrance at East 20th Street, and two exits, at East 18th Street and East 24th Street. At the exit shafts, traditional excavation methods will be used to connect the new trunk sewer to existing sanitary drainage.  

Recent projects completed by Metro Vancouver have shown micro-tunnelling to be less disruptive and a less expensive way to replace large-diameter sewer mains compared to traditional excavation methods. 

Traffic impacts

While the micro-tunnel construction method of sewer replacement significantly minimizes impacts on traffic, there will be some disruptions and delays. We expect to maintain a minimum of one lane in each direction at all times through all affected areas on Mountain Highway, with the exception of vehicle access to and from East 20th Street via Mountain Highway, which will be closed for the duration of construction. The intersection at East 24th will also require full closure for a period of time, likely in spring 2023. 

Safe pedestrian routes will be maintained at all times.

Noise impacts

Micro-tunnelling requires the temporary set up of a separation plant close to the work site to sort the materials (dirt, rocks, etc.) pulled from the tunnel. This separation plant will be located in the BC Hydro right-of-way, off Mountain Highway, and is expected to produce noise and vibration.

Depending on ground conditions, 24-hour work may be required during tunnelling work. 

We will make every effort to manage these impacts where possible by implementing noise and vibration reduction best practices and conducting noise monitoring and measurement throughout the project.


The trunk sewer section between East 24th and East 18th Street on Mountain Highway is nearing the end of its expected service life and is undersized to meet additional demands. 

With several Lynn Valley Town Centre projects nearing completion and occupancy, demand on the existing sewer trunk is expected to increase. In addition, during wet weather, this section of sewer is known to run above capacity as rainwater leaks into defects of the aging infrastructure. Due to climate change, the increasing frequency of significant rainfall events will further the strain. 

The new sewer with upsized pipe will be capable of handling increased capacity demand now and in the future and is expected to have an 80- to 100-year lifespan. 

Get significant project updates delivered to your inbox

Submit your name and email address, and we'll keep you updated about progress with this project.  

Was this page helpful?

Thanks for your input.