Tree Root Intrusion in Sewer Lines

How Roots Find Your Pipes

Tree roots are naturally attracted to the moisture, nutrients, and oxygen available in sewer lines. Roots can detect the vapor escaping from tiny cracks, loose joints, or aging pipe materials and grow toward the source. Once a root tendril enters a pipe through even the smallest opening, it rapidly grows and branches, creating a dense mass that traps waste and eventually blocks the pipe entirely. Older clay tile and Orangeburg (tar paper) pipes are particularly susceptible because their joints provide easy entry points.

Signs of Root Intrusion

Recurring sewer backups that seem to clear after snaking but return within weeks are the hallmark of root intrusion. You may also notice gurgling drains, slow drainage throughout the house, or sinkholes and wet spots in the yard above the sewer line. A video camera inspection is the definitive way to confirm root intrusion — the camera will show roots entering through joints, cracks, or break points in the pipe, often appearing as hairy masses partially or fully blocking the pipe interior.

Removal Methods

Mechanical root cutting with a sewer snake equipped with a root-cutting head (rotating blades) is the most common removal method. This clears the blockage and restores flow but does not prevent re-growth. Hydro-jetting with specialized nozzles can cut and flush roots more thoroughly. Chemical root treatments using copper sulfate or dichlobenil (sold as root killer) can be flushed into the sewer line to kill roots inside the pipe without harming the tree. Foaming root killers are most effective because the foam coats the upper portion of the pipe where roots often enter.

Permanent Solutions

For long-term solutions to root intrusion, consider pipe relining (CIPP), which creates a seamless joint-free pipe inside the existing line, eliminating entry points. If the pipe is severely damaged, replacement with modern materials (PVC or HDPE) with properly sealed joints prevents future root entry. When landscaping, plant trees at least 10 feet from sewer lines (30 feet for aggressive species like willows, poplars, and maples). If you must plant near a sewer line, install a root barrier — a physical or chemical barrier that redirects root growth away from the pipe.