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Jefferson and Hood Street Surface Water Interceptor

Project Description

City of Tacoma began construction of a large 60-inch diameter interceptor stormwater pipeline and a new outfall into the Thea Foss Waterway in fall 2021. This project will improve existing storm sewer system capacity, help reduce flooding events, and support future growth in the downtown area. The project is anticipated to be complete in fall 2022.

The City hired a design build team of James W. Fowler Co. and Kennedy/Jenks Consultants to design and construct this new stormwater pipeline. See the map below for the project area.

JHI Project Map



Project Goals

  • Address flooding that occurs in the lower downtown area due to capacity limitations in the existing stormwater system.

  • Provide stormwater conveyance capacity for future growth in the downtown area.

  • Deliver project improvements that represent the “best value” to Tacoma’s surface water ratepayers.

  • Mitigate construction impacts on the downtown community, including adjacent local businesses and the public.

Project Video



Location of Project

Construction will occur in the downtown area along S. 19th Street, Jefferson Avenue, S. 17th Street Prairie Line Trail, S 15th Street and A St., and Dock Street. All work will be done within the city right of way. Scroll down for project updates for each location.


Construction Methods

Most of the sewer pipe will be installed using open-cut construction. In open-cut construction, crews dig from the surface to the pipe, depth, lay the pipe, then cover the pipe and restore the surface. 

Open Cut Construction Image


There are a few areas that require a trenchless or “microtunneling” method. This method does not require digging from the surface to the pipe depth. Instead, two shaft are built on either end of the pipe. Then the pipe is installed using a hammer, auger, drill, or microtunneling machine. This method is only feasible in certain types of soils and conditions.


We expect to use trenchless construction in the following places along the stormwater interceptor pipeline:

  • Under Dock Street
  • Under the BNSF railroad tracks
  • Under the Pacific Avenue / Link Light Rail crossing trenchless construction

Construction Impacts

Construction will start in late October 2021 and take approximately one year to complete. During construction you can expect:

  • Weekday work hours, 7 AM – 5 PM. Minimal night and weekend work may be required.
  • Construction noise, dirt, and vibrations
  • Lane restrictions
  • Full street closures. Local access will be maintained.
  • Pedestrian detours
  • Parking and delivery restrictions

Note that the start date, duration, and work hours are subject to change due to permitting, weather, and other factors. To sign up for project news and updates, click here.


Project Benefits

This stormwater improvement project is an important part of the underground network of pipes that help reduce flooding in and around the downtown area. The City is replacing this pipe in efforts to improve existing storm sewer system capacity, help reduce flooding events, and sustainably support future growth in the downtown area.


Construction Update (March 18, 2022)


South 17th Street between Pacific Avenue and Commerce Street: 

Crews working for the City of Tacoma are relocating a sanitary sewer pipe along S 17th St between Pacific Ave and Commerce St. The work is located near a Sound Transit light rail power pole. To maintain safety of the crew and stability of the light rail pole, Sound Transit will deactivate the Link light rail between 10 p.m. and 7 a.m. so crews can safely complete utility work outside of peak traffic hours. This work will be noisy and is anticipated to last up to 5 days. This after-hour work has been approved by a City of Tacoma noise variance. We apologize for any inconvenience and appreciate your patience. To learn more about the night work and what to expect, click here.


1147 Dock Street: 

Crews have completed installing the bracing needed to stabilize underground structures that will support installation of a new stormwater pipe. Crews also completed building the new outfall that will serve as a discharge into the Thea Foss Waterway. Construction will continue at this location until fall 2022 to install the stormwater pipe, backfill the soil, and permanently restore the area. Below is a picture of crews working at night to install a portion of the new outfall into the Thea Foss Waterway. Crews conducted outfall work at night to take advantage of the lowest daily tides which help crews keep the work zone dewatered.


Picture of project outfall

The outfall is designed to support stormwater drainage of more than 90,000 gallons per minute. At that flow rate, it would take about seven minutes to fill an Olympic-size swimming pool.


15th and Dock Street:

Crews are driving sheet piles to create launch and receiving pits for tunneling the new stormwater pipe underground. This work requires closing one lane of traffic on Dock Street so that crews have room to safely drive sheets with excavators. Work hours are Monday through Saturday, 7 a.m. - 5:30 p.m. Crews will open both lanes of traffic outside of work hours. Uniformed police officers are on site to help direct traffic. This traffic pattern is expected to last up to two months.


S 17th Street and Pacific Ave:

Starting February 7, 2022, crews mobilized at S 17th St between Pacific Ave and Commerce St to begin to relocate a sanitary sewer pipe before installing the large diameter stormwater pipe. The sanitary sewer relocation work will last up to six weeks. Construction crews will then work at S 17th St and Pacific Ave to dig two large pits used for trenchless construction under Pacific Ave and the Link light rail crossing (see project map below for approximate location). Construction activity will take place on weekdays, from 7 a.m. - 5:30 p.m.


S 17th St between Pacific Ave and Commerce St will remain closed for up to 8 months while crews relocate a sanitary sewer pipe, dig reception shafts for tunnel drives, install a 60-inch stormwater pipe, and restore the roadway.


As early as summer 2022, crews will close S Hood St at Pacific Ave for up to three days to install new inlet drains and catch basins. Crews will then return to restore the roadway and Prairie Line Trail.


Contact Information

For additional information, call the project hotline at (253) 279-5509 or email the project team. To signup for project news and updates, click here.