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Puget Sound Energy natural gas projects

Tolt 16-inch natural gas line


2018 project updates

  • Gas line work has been rescheduled to 2018. Next summer, crews from PSE and our contractor will begin work to improve the natural gas system in King County by installing roughly 1,800 feet of 16-inch natural gas pipeline along the Seattle Public Utilities (SPU) Tolt pipeline corridor between Avondale Road NE and Mink Road NE.
  • You may have received a mailed notice from King County’s Department of Permitting and Environmental Review providing additional information about the environmental review and permit application for this project.
  • If you have any questions about the project, please reach out to us at 1-888-404-8773 or


Project overview

As demand for natural gas grows, Puget Sound Energy's existing 8-inch high pressure natural gas line serving northeast King County is nearing its capacity limits 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 plans to upgrade the natural gas system in northeast King County.  

PSE will install approximately four miles of new 16-inch high pressure natural gas pipeline and construct a new gate station in the area. 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 necessary 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:
    Construct 2.8 miles of 16-inch natural gas pipeline along the existing Seattle Public Utilities Tolt utility corridor between Mink Rd NE and 155th Ave NE. This project began  construction in 2015. Construction is expected to resume in 2018. Please see the Phase 1 aerial map for reference.
  • Phase 2:
    Construct 1.2 miles of 16-inch natural gas pipeline along the existing Tolt utility corridor between 216th Avenue Northeast and Mink Road Northeast, where it will connect to the segment of pipeline constructed in Phase 1. Plans also entail constructing a new gate station near the intersection of 216th Avenue Northeast and the Tolt corridor. We expect to construct this phase in 2022 based on current growth forecasts. Please see the Phase 2 aerial map for reference.
As growth continues in the area, there is a potential for a third phase in PSE's long-term plan. The third phase would run approximately 1.9 miles along the Tolt utility corridor between 155th Ave NE and 132nd Ave NE (see the project map and Phase 3 aerial map for reference). We don't have a timeline for this phase of work, but will be monitoring population growth, future planned residential and commercial development and natural gas usage in the area over the next several decades to help us determine when the third phase would be 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. We are using installation techniques that will allow us to minimize disruption of nearby wetlands and critical areas, as well as to the corridor itself. Additionally, because the Tolt corridor is popular with local walkers, runners, cyclists and equestrians, we're aiming to keep the majority of the corridor open during construction so it can still be used for recreational purposes. Additionally, our team has developed a construction outreach plan aimed at keeping the community informed of work-related closures, detours and work schedules. After construction is complete we'll 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, service lines and, ultimately, to 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. We aim to complete this work with as little disruption as possible.