Instances of pipes being broken by the growth of roots are rare, but blockage of damaged pipes is not uncommon. As roots enlarge, they may occasionally break the pipes and enter the cracks. More commonly, the pipes fail (especially at the joints) due to age or slight movement of the soil, allowing roots to invade. Moisture and nutrients released from ruptures can stimulate root growth toward the break in the pipe. Once a root enters a sewer pipe, the conditions of aeration, moisture, and nutrients are quite favorable for rapid growth.
Species that are naturally found in wet areas such as poplars, willows, and silver maples, are commonly associated with clogged pipes. Blocked sewers usually must be cleared mechanically. Mechanical routing may be needed on an annual basis. Registered chemical treatments are available. The main advantage of these products is that they can be placed into the sewer as a foam for more effective contact with roots; however, it is essential to follow label directions. The only permanent solution to the problem, however, is to replace ruptured pipes. Modern materials and joints should prevent most problems in the future.