A homeowner can use a foaming root killer that contains an herbicide to kill and prevent the regrowth of the tree roots. Other preventative measures include pouring sodium chloride, copper sulfate crystals or rock salt into the toilet bowl and flushing them into the pipes.
If the tree roots are completely clogging the sewer pipes and sewage is backing up into the house, a plumber can use a powered sewer auger to cut and clear the roots from the pipes. After the pipes are cleared, chemical methods may be used to prevent regrowth of the roots.
While these chemicals are effective in preventing root growth into the sewer lines, the homeowner risks killing the tree and other vegetation growing over the pipes. All chemical remedies should be used according to the manufacturer's directions.