Pearl Street Drainage Improvement Project

Image map of Pearl Street project location.
The City will make drainage improvements in west Beacon Hill.

Project Description

Reducing stormwater flooding and backups in your neighborhood
Seattle Public Utilities is working on a capital improvement project to upgrade the combined sewer infrastructure in Seattle’s Beacon Hill neighborhood.  
The goal of the Pearl Street Drainage Improvement Project is to reduce storm-related sewer backups and flooding in the area, which will help protect public health and the environment as well as improve service reliability.
This project involves:

  • Installing a new sewer pipe along Corson Ave S from S Ferdinand to S Dawson streets
  • Expanding existing pipe between S Dawson and S Bennett streets using trenchless technology (i.e. no excavation for pipe installation) and installing a maintenance hole at the S Bennett street end
  • Building a large underground storage tank to capture sewage and stormwater during large storm events and then slowly release it into the pipes that run under S Dawson St
  • Constructing a small facility building on the south side of the intersection of Corson Ave S and S Dawson St (view Facility Building Design)
  • Installing three aboveground electrical cabinets on the north side of S Dawson St


This project is located in west Beacon Hill near Maple Elementary School with work occurring on Corson Ave S from S Ferdinand to S Bennett streets, the street end of S Bennett St, and on S Dawson St between Corson Ave S and 12th Ave S. Most of the work will occur on S Dawson St. Visit project area map.

What's Happening Now?

The Project Team completed design and construction will begin in late June 2020. 

Prior to construction, residents can expect:

  • Puget Sound Energy will relocate a service on S Dawson St. (This work was completed)
  • Seattle City Light (SCL) will install a temporary service at the entrance to the alley on the north side of S Dawson St.
  • During this work, there will be a brief, temporary service disruption. SCL will provide notice to impacted residents.

Once construction begins, work will be conducted in overlapping phases for approximately 16-18 months:

  • The contractor expects to begin work on Corson Ave S this summer.
  • S Dawson St, including the entrance to the north-south alley from S Dawson St, will be closed for the duration of work. Residents will continue to have vehicular access to the alley via Pearl St.
  • Prior to the closure of S Dawson St, the contractor will perform alley improvements between S Dawson St and S Bennett streets west of 12th Ave S to minimize construction impacts to adjacent residents during work.
  • Work on S Bennett St will be primarily trenchless with minimal impacts.
  • Paving and other restoration work for the entire worksite will likely occur at the end of the project.

SPU is reaching out to nearby residents to share project updates and potential construction impacts prior to construction. In the meantime, please review the Project Fact SheetConstruction Phase Overview, and Construction Phase Map for more information about the project and signup to receive project email updates.

Anticipated Impacts

You can expect:

  • Construction noise, dirt, dust, and vibrations
  • Crews to work 8 to 10 hour days Monday through Friday. Work hours and days may vary based on work being preformed. Evening or weekend work may be required later in construction, advanced notice will be provided.
  • Increased construction traffic and staging of large equipment in the area
  • Work will typically occur during weekday, daytime hours, but some night and weekend work may be required. Additional notice will be provided via the project email list prior to night or weekend work.
  • Temporary, short-term service interruptions to gas, water, and electricity to connect to new services. Impacted residents will be notified prior to this work.
  • Lane closures and parking restrictions along Corson Ave S for sewer pipe installation. Note, this work will take place during summer months.
  • 24 hr/day full road closure and no parking on S Dawson St between Corson and 12th avenues for approximately 1 year.
  • Short-term driveway access and street parking restrictions at the street end of S Bennett St for maintenance hole installation and installation of new pipe using trenchless technology.
  • The contractor will coordinate mail delivery and garbage/recycling/compost pick-up to avoid service disruptions. Please contact the project team if you experience any service disruptions.
  • The contractor will provide access to emergency services, as needed, during construction
  • Site restoration, which may involve 24/7 road closures for repaving work. Additional notification will be provided prior to this work.

Community Engagement

Please subscribe to the project email list to receive up-to-date information prior to and during construction.


Early 2018 to Late 2019

  • Project team working on design and permitting
  • Shared updates with nearby residents

Early to Mid-2020

  • Finalize project design and prepare for construction
  • Provide project and construction-related updates
  • Pre-construction activities including Puget Sound Energy and Seattle City Light work to begin as early as May 2020
  • Construction scheduled to begin. Once started, work is expected to take about 16-18 months.

Summer 2020

  • Construction scheduled to begin
  • Once started, work is expected to take about 16-18 months. Note, start date and duration are subject to change. Residents will receive additional information about the schedule if schedule changes becomes necessary.

Late 2021

  • Project Completion