Skip to main content
King County logo

Every property has one sewer pipe that connects the building(s) to the larger sewer and treatment system. Side sewers could be made out of clay, iron, plastic, concrete or brick depending on the age of the home or buildings -- maintenance is the property owners responsibility. Always call before you dig!

To prevent side (lateral) sewer problems know your pipe – where it is located, how old it is and any known tree root problems. Maintain your side sewer by not flushing garbage or rinsing grease down drains, and by planting trees and shrubs with low root damage potential.

Did you know? Side sewers are often the age of your house and can be made out of clay, brick, concrete, iron, or plastic. Tree roots commonly enter sewer pipes and can cause clogs and overflows.


  • When buying a new house always get a side sewer inspection.
  • If you are remodeling or landscaping make sure you know where the side sewer is first!
  • Know the 24-hour emergency contact for your local sewer utility for issues with odors or overflows.
  • Know how old your sewer line is and the condition it is in. Plan to have it eventually replaced if it has cracks and leaks. The farther ahead you plan the more options you have for replacement and maintenance and the less chance of an emergency overflow or broken pipe. Check with your local city for permitting questions.

Helpful Hint: Slow drains and/or sewer odors can indicate side sewer problems.

disconnect a downspoutDisconnecting a downspout consists of cutting the downspout, capping the drainage line, and redirecting the flow.

Side sewer problems (root intrusion, cracks, faulty connections)A side sewer connects the house to the local sewer line in the street. Maintenance of a side sewer is the property owner's responsibility.

Side sewer (excavated) completely blocked by rootsA segment of excavated side sewer completely blocked by roots.

Sewage Overflow Card, front sideDownload the Know Your Sewer System card