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Environmental Services

working for clean rivers

Phone: 503-823-7740

Fax: 503-823-6995

1120 SW 5th Avenue, Room 1000, Portland, OR 97204

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NW Flanders Street and 11th Avenue Sewer Repair Project

Sign up for email construction updatesEnvironmental Services is designing a project to repair about 250 feet of 100-year-old public sewer pipe in NW Flanders Street between NW 12th and 11th avenues (see map). 

The public sewer in NW Flanders Street between NW 12th and 11th avenues was constructed in 1916 and is showing signs of wear and tear, including cracks, tree root intrusion and structural ovalling due to stresses on the pipe. This project will reduce the risks of sewage releases to businesses and streets and sewer service interruptions that could occur as a result of pipe collapse.


Construction is anticipated to begin in February or March 2017 and take three months to complete. 

Construction Methods

This project will repair the 100-year-old sewer pipe using a trenchless construction method called cured-in-place-pipe lining (CIPP). Work crews access the sewer from manholes to insert a flexible liner inside the old pipe. Hot water or steam inflates and cures the liner, which gradually hardens to form a rigid, smooth surface that seals cracks and restores the pipe to near-new condition. For details about CIPP and photos, click here.

The project will also repair or replace storm drain inlets, manholes and up to 100 feet of service laterals that connect private properties to the public sewer. Open trench excavation will be necessary to complete these additional repairs to the public sewer system.

Historic trolley rails intersect the sewer at NW Flanders and 12th and the service laterals on Flanders. The project will remove the rails and ties before repairing the public sewer. All of this work will be completed during regular daytime hours.

Potential Night Work for One Day

Because the process to complete the CIPP lining may go past the typical 7:00 a.m. to 6:00 p.m. daily work hours, the city will apply for a noise variance. Nighttime work would require the use of a generator, air compressor, pump, boiler and lights. Pumps may operate into the night until the liner hardens. Potential night work should only be one day and night during the project and create low-level noise.

Portland noise code allows construction from 7:00 a.m. to 6:00 p.m. Monday through Saturday. Work after 6:00 p.m. and before 7:00 a.m. and all hours on Sundays requires a noise variance from the Portland Noise Office. Your comments regarding the potential night work for one day are valuable and you can submit them to the Portland Noise Office by letter or email. Please submit your comments by November 11 to:

Portland Noise Office
1221 SW 4th Avenue, Suite 110
Portland, OR 97204

Or send an email to the Portland Noise Office.

Traffic Controls

During construction of this sewer repair project, Portland Streetcar operations on NW 11th Ave will not be disrupted. The project will keep all lanes on NW 11th Ave open at all times. Traffic on NW 12th Ave may see lane restrictions during work hours, but the street will remain open.

  • Construction hours will be 7:00 a.m. to 6:00 p.m. Monday through Friday. The contractor may also schedule work during the same hours on Saturdays. One day/night of extended hours between 6:00 p.m. and 7:00 a.m. may be required to harden the CIPP lining.
  • Construction creates noise, vibration and dust and disrupts normal neighborhood activity.
  • The contractor will maintain local access, but construction may impact normal use of driveways or business entrances.
  • You should expect traffic delays in and near the work area. Please observe traffic control signs and follow the directions of flaggers.
  • On‐street parking will be restricted in and near the work zones to create a safe work environment and to stage equipment and materials.
  • Some equipment and materials may be stored on your street or nearby streets overnight.
  • There may be periods of inactivity between construction phases due to a variety of factors including weather, subcontractor schedules and availability of materials.
  • A city inspector will be on-site during work hours and may be able to assist you with an immediate need during construction.
  • Sewer, water and other utilities will remain in service during construction.

For More Information

Contact Ashley Tjaden by phone at 503-823-5281 or send Ashley an email with “NWFlanders” in the subject line. Please let us know if you have concerns such as business operations, disability issues, medical or business deliveries, or other concerns about how this project might affect your property. If you provide your property address, we may be able to provide you details about what to expect in construction at your property.

Sign up now for periodic email updates by clicking the SIGN UP! button above. We'll keep you posted about the construction schedule, traffic and parking controls,  and construction activities as the project evolves.


Construction Methods

Learn more about sewer construction methods