Puget Sound Energy natural gas projects

Tolt 16-inch natural gas line

2018 project update

Tolt Pipeline Trail closure - June through September

  • Crews are working to install 1,800 feet of pipeline between 400 feet west of Avondale Rd NE and Mink Rd NE. Refer to Phase 1B in blue.
  • For safety reasons, this section of the Tolt Pipeline Trail will be closed June through September.
  • To ensure safety, we ask that trail users adhere to the trail closure and do not attempt to detour around it.
  • This project will replace the aging creosote bridge across Cottage Lake Creek with a new bridge. We have worked extensively with the relevant agencies to develop a solution that would minimize impacts to the natural habitat, and the result is a bridge design that will span the original flood plain of Cottage Lake Creek.
  • Our work was permitted during summer to minmize impacts to the resident Puget Sound Chinook and Steelhead.

Project overview

As demand for natural gas grows, PSE's existing 8-inch high pressure natural gas line serving northeast King County is nearing its capacity during cold winter days, when people use more energy to stay warm. The system's capacity constraints impact our ability to supply natural gas at an adequate pressure to reliably serve more than 27,000 residential, commercial and industrial customers in the Woodinville, Bothell, Kenmore, Kirkland and unincorporated King County areas.

In order to maintain the current reliability of the natural gas system in the area and ensure we can continue to provide our customers with dependable service in the future, PSE has been working to upgrade the natural gas system in northeast King County.

Project scope:

  • Installation of approximately four miles of new 16-inch high pressure natural gas pipeline
  • Construction of a new gate station near the intersection of 216th Ave NE and the Tolt Pipeline Trail.
  • A gate station is a facility where natural gas is metered, reduced in pressure, and injected with a strong odorant called mercaptan, which gives the gas its familiar rotten-egg smell.
  • When complete, this new infrastructure will add vital capacity to the existing system and reinforce the current natural gas pipelines in the area, allowing PSE to continue providing our customers with reliable natural gas service well into the future.

Project timeline:

  • Phase 1:
    Construction of 2.8 miles of 16-inch natural gas pipeline along the existing SPU utility corridor, between Mink Rd NE and 155th Ave NE. This phase began construction in 2015. Construction of the remaining 1,800 feet will commence in June 2018. Refer to Phase 1 aerial map for locations.
  • Phase 2:
    Construction of 1.2 miles of 16-inch natural gas pipeline along the existing SPU utility corridor between 216th Avenue NE and Mink Road NE, where it will connect to the segment of pipeline constructed in Phase 1. Construction of a new gate station is also included in this phase. Construction for this phase is planned for 2022 and timings are based on current growth forecasts. Please see the Phase 2 aerial map for reference.

As growth continues in the area, there is potential for a third phase in our long term plan to ensure reliability. The third phase would run approximately 1.9 miles along the Tolt utility corridor between 155th Ave NE and 132nd Ave NE.

We will continue to monitor population growth, natural gas usage, as well as future planned residential and commercial development in the area over the next several decades to help us determine when the third phase is necessary for our customers. Current high-level planning estimates suggest this work would occur around 2033.


View full-size project map It's our goal to minimize construction impacts in the Tolt corridor, and for the people who utilize it, as much as possible. Our construction methodology was chosen to minimize impacts to the natural habitat and nearby wetlands, as well as to the corridor itself. After each stage of construction is complete, we will progressively restore the corridor back to its original condition.


Safety is our top priority when it comes to designing, constructing, operating and maintaining a natural gas system that serves more than 800,000 PSE customers. We are committed to listening to our customers, maintaining an informed and open conversation about our work, and being responsive to customer needs. PSE monitors over 26,000 miles of natural gas pipeline across six counties in our service area. Click here for more information on natural gas safety.

How does natural gas get to my home or business?

Natural gas is a fossil fuel composed almost entirely of methane. Interstate pipelines transport natural gas to regional natural gas systems, where it is metered and delivered through a network of local mains and service lines, before reaching customer homes and businesses. View How Natural Gas Gets to You for more information.

Committed to keeping you informed

PSE will continue to provide updates to the community. We'll notify residents who live near the project area when construction will occur. Our aim is to complete this work with minimal disruption.

Contact us

We welcome your questions and comments. Please contact:

Dave Jenness
Senior Project Manager