Sewer line roots in pipes can best be controlled by mechanically removing the roots with a sewer cable and then treat the sewer line with a foaming root control. Leave it undisturbed for six hours for the best results. Foaming so it coats the top of the sewer line where roots can enter. We now recommend a root killer called Roebic’s Foaming Root Killer. It is sold in one-pound containers at most hardware stores.
People have a sewer line that clogs yearly with roots. A sewer company opens the drain and I use copper sulfate to kill the remaining roots. The old standby root killer, copper sulfate, is being discouraged by treatment plants due to the damage it causes to the biology at the plant.
To use, pour Roebic’s Foaming Root Killer into the main cleanout and chase it with three gallons of water. I use two gallons of water when the roots are closer than 50 feet from the house. Ask your sewer guy what the distance his cable was out when he hit the roots.
Immediately replace the sewer cap after pouring the water in the cleanout, the foam could backup out the drain. Do not use this product with a clogged drain or you could be up to your knees in foam.
When getting the line cleaned, start with a small cutter so as not to jam the cable in the roots. Then work up to larger cutters to remove as much of the roots as possible. Be very careful not to get a large cutter tangled with roots and not be able to remove it out of the cleanout.
Many sewer men that encounter large clusters of roots will only be able to run a small cutter through the line. They will then recommend using copper sulfate for a couple of weeks to weaken the roots and then return to run the larger cutters.