Seattle Public Utilities Mami Hara, General Manager/CEO

Side Sewers

side sewer

What is a side sewer? What does it do?

A side sewer carries wastewater from a building's sinks, toilet and drains to the public sewer in the street.

Who takes care of the side sewer?

If you own your home or building, you own your side sewer to the public sewer main, located under a street near your home. Follow these steps to care for your side sewer:

  1. Know where your side sewer is located.
    Download your property’s side sewer information from the Seattle Department of Construction and Inspections (DCI) website.
  2. Understand its condition.
    Find a plumber or sewer inspector who can run a video camera through your side sewer. This will tell you if you have any problems with your side sewer like blockages from roots or a broken pipe. It is good to know about these problems so you can prevent a sewer back-up in your home.
  3. If needed, clean or make a repair to your side sewer.
    Regular cleaning can help prevent costly repairs. Hire a registered side sewer contractor to clean your side sewer, especially if roots are present. A broken side sewer also needs to be fixed. Learn more about how to repair or replace a side sewer.
  4. Flush only toilet paper and properly dispose of grease.
    Items such as wipes, sanitary products and grease can clog toilets and pipes in your home, causing sewage to overflow in bathrooms and kitchens. Watch this SPU pump station video to see what happens to our pipes when trash is flushed. Learn more about how to dispose of grease.

If you have a sewer backup:

  1. Call Seattle Public Utilities at (206) 386-1800 if you see sewage or dirty water coming from a sink, toilet or drain. Seattle Public Utilities may come check the public sewer for issues.
  2. Call a plumber - View our Troubleshooting Your Sewer Problem (pdf) for tips and questions to ask.
  3. Clean up sewage spills as soon as possible to protect people – especially small children – from harmful bacteria and viruses. Guides to a safe clean-up include:

Watch this sewer backup video for more information.

More information on common sources of side sewer problems:

  • Offset joints. Uneven connections between pipe segments can lead to sewer problems.
  • Sagging pipes. If a side sewer line dips down, a backup is possible.
  • Cracks and fractures in pipes. Due to poor installation, poor soil bedding, root penetration or structural deterioration.
  • Debris/grease in pipes. Grease, fat, oil, wax and other debris contribute greatly to sewer problems.
  • Holes in pipes. Can cause surrounding soils to erode into the pipe or cause debris buildup in the pipe.
  • Root damage. Tree roots can penetrate older clay and concrete pipes.
  • Exposed aggregate. Most common critical defect in side sewers constructed from concrete.