How Tree Roots Invade and Damage Sewer Lines

Tree roots don’t typically “break” sewer lines from the outside in the way people often imagine. Instead, most damage happens when roots find a pathway—such as a crack in a pipe, a loose joint, or a weak spot near a manhole—and then grow into that space.

Sewer pipes carry wastewater and are designed to keep water contained. But even minor defects can create openings that roots can exploit. Once roots enter, they respond to the wet, nutrient-rich environment inside or near the line, which helps them proliferate and continue expanding the damage.