What are the common causes of a sewer line backup?

Common causes of a sewer line backup include tree root intrusion, heavy sludge or grease buildup, and damaged or collapsed pipe sections. Tree roots are a frequent culprit our technicians identify during video camera inspections because they grow toward moisture and invade small pipe openings. Sludge, grime, and rust scale can also narrow the pipe until normal flow stops, while broken or collapsed areas block the line entirely. In practice, we confirm the cause with a high-definition camera, then clear the line with hydro-jetting or rooter equipment, or restore the pipe with trenchless relining; if the pipe has failed, excavation and replacement may be required. Our crews regularly handle these scenarios for homeowners in Snohomish and nearby communities using the same diagnostic-first approach. If sewage is backing up, stop using water and schedule a camera inspection before further damage occurs. <br/> Updated: 2026-04-07 <br/> Need help in Snohomish, WA? Call (425) 387-1507 or book online.