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?

Construction began in late June 2020, and it will take about 16-18 months to complete this project.

Corson Ave S Sewer Replacement

The work on Corson Ave S is complete as of March 2021, with only a few landscaping details and crosswalk striping remaining.

Work on S Dawson St

S Dawson St is currently closed to through traffic between Corson Ave S and 12th Ave S through the end of construction, which is currently scheduled for late summer/early fall 2021. During this closure:

  • Residents will still have pedestrian access to their homes.
  • Local access will be maintained.
  • The contractor will work to maintain access to driveways to the east of the storage tank construction area, but driveways may be blocked intermittently during working hours.
  • The alley entrances on the north and south side of S Dawson St will be closed. Residents connected to the alley on the north side will continue to have vehicular access via S Pearl St, and residents on the south side will have access via 12th Ave S.

Upcoming support system installation and excavation work for the underground storage tank will involve:

  • Installation of the east/west piles, which are scheduled to be completed in early April.
  • After east/west piles are installed, the contractor will begin excavation of the storage tank area, which will include noise, dirt/dust, and construction traffic. This work is scheduled to begin mid-April and will take about 5-6 weeks.
  • Once the structural support system is installed, the contractor will begin excavating the area where the construction on the large underground storage tank and other utility upgrades near the intersection of S Dawson St and Corson Ave S.

During the tank installation work, residents can expect:

  • Construction noise and vibrations, especially during the pile drilling.
  • Construction traffic in and out of the site to haul away excavated material.
  • Residents may experience temporary, short-term utility service interruptions while the contractor relocates and reconnects services. Impacted residents will be notified prior to this work.

Work on S Bennett St

This work is currently scheduled to begin in late spring/early summer 2021. During this phase of work, residents can expect 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.

Additional notice will be provided prior to this work.

Learn more about what to expect during construction by reviewing the Construction Phase Overview, and Construction Phase Map and signup to receive project email updates.

Anticipated Impacts

In general, you can expect:

  • Construction noise, dirt, dust, and vibrations.
  • Crews to work 8 to 10 hour days Monday through Friday. Evening or weekend work may be required. When possible, advanced notice will be provided.
  • Increased construction traffic and staging of large equipment in the area.
  • Road/lane closures and parking restrictions near the work areas. Please pay attention to onsite signage and park your car in an alternative area, if needed, to avoid being towed.
  • The contractor will coordinate garbage/recycling/compost pick-up and access for mail delivery for homes near construction. The contractor may relocate your garbage/recycling/compost bins, if needed, to facilitate pick-up. In the event of a missed pick-up, please contact the project team.
  • The contractor will work to provide access for USPS and other delivery services, as needed.
  • Emergency vehicles will continue to have access to homes, if needed.
  • Paving and other restoration work, which may require temporary 24/7 closures, to be performed throughout construction.

Community Engagement

Our email list will be the primary means of sharing timely information. Please subscribe to the project email list to receive construction updates.


Early 2018 to Late 2019

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

Early 2020

  • Finalize project design and prepare for construction
  • Provide project and construction-related updates
  • Pre-construction activities including Puget Sound Energy gas line relocation

Mid 2020

  • Construction began in late June 2020, and it is expected to take about 16-18 months. 
  • For more information about construction phases, please check out the Construction Phase Map.

Late 2021

  • Project Completion

Note, schedule is subject to change. Residents will receive additional information via the project email list about the schedule if schedule changes become necessary.