Tree roots seek out sewer lines. Contact your plumber or local hardware store for the best ways to prevent roots from plugging your sewer lines. Also ask how frequently the recommended root control method must be repeated to keep roots out of the sewer lines.
Why Roots Seek Out Sewers
Tree roots seek out sewers because sewers contain moisture, nutrients and oxygen. The tree roots grow through cracks or joints in the sewer line. Once in the sewer lines, the roots will grow up and down the sewer lines, eventually plugging the lines.