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How to Kill Roots in Sewer Pipes

By Meg Butler ; Updated September 21, 2017

Deep tree roots are naturally drawn to cracked sewer pipes. These compromised pipes leak water and nutrients into the soil, attracting the roots. Once a tree root finds its way into a crack in a sewer pipe, it will grow rapidly. Tree roots that grow large enough will block the sewer line and cause sewage to back-flow into your yard or basement. But although the problem may seem disastrous, you don’t have to kill the trees to kill the roots that have grown into your sewer pipes. A simple foaming septic root killer will kill interfering roots on contact while keeping the tree safe.

Pour the foaming root killer into the sewer system. The best method is to pour the root cleaner into your cleanout (the capped pipe on your property that directly accesses the sewer line). If you don't have a cleanout on your property, flush the foaming root killer down the toilet.

Turn off all the water in your home. Keep it off for at least one hour after the foaming root killer treatment.

Re-treat the sewer system with foaming root killer annually. Most foaming root killers kill roots and retard their growth, but other roots may find their way into other compromised sections of your pipes. Pre-emptive treatment is the best approach.



  • The amount of foaming root killer you need depends on the length of your pipes and the strength of the product.
  • Foaming root killer kills tree roots instantly, but it may take a few weeks for the roots to degrade enough to clear the blockage.

About the Author


Based in Houston, Texas, Meg Butler is a professional farmer, house flipper and landscaper. When not busy learning about homes and appliances she's sharing that knowledge. Butler began blogging, editing and writing in 2000. Her work has appered in the "Houston Press" and several other publications. She has an A.A. in journalism and a B.A. in history from New York University.