What are the common causes of a sewer line backup?

A sewer line backup happens when wastewater flow is blocked or the pipe fails. The most frequent trigger our plumbers see is tree-root intrusion that narrows the line and snags debris. In our day-to-day work around the West Valley, we also see backups from aging materials that have shifted, corroded, or sagged over time.

Watch for these common causes:

• Grease, scale, and sludge buildup that constricts the pipe interior
• Wipes, hygiene items, and other foreign objects that don’t break down
• Offset joints, bellies (low spots), or crushed sections from soil movement
• Corroded, cracked, or collapsed clay, cast iron, or PVC segments

For confirmation without guesswork, a $75 Sewer/Main Line Camera Inspection with 4 Hour Arrival can pinpoint the blockage location and condition before repair options like trenchless methods are considered. If you see multiple drains backing up at once, stop water use and book a camera inspection to prevent an overflow.

Updated: 2026-05-29

Need help in Sun City West, AZ? Call (602) 899-0899 or book online. "Main sewer Line repairs... they showed me the root blockage. I was highly satisfied and would recommend them." — Julie H.