Removal of tree roots in a sewer line requires using chemicals, mechanically cutting or digging the roots out of the line, or killing the roots using a hydro jetter. Each method is effective in its own way, but they vary greatly in ease of use and price.
Chemical tree root removal requires the use of copper sulfate crystals. Trees don't like this chemical, and the roots die trying to enter the sewer line. Many commercial tree removing chemicals foam, and cover a large area.
Mechanical removal of tree roots is more labor intensive. To remove tree roots, use a mechanical auger with a rotating spiral head. The auger will chop up the roots into small manageable pieces, and they will need to be removed. it is important to note that cutting the roots will only spur the tree to create more roots, which will cause a problem later on.
Using a hydro jetter to remove tree roots is the most expensive technique, but also a very effective method. This method involves using a jet of water that shoots out of a pump at 4,000 psi. After breaking the roots, the jetter can be used to flush the pieces out of the sewer line. This method should be followed up by a chemical tree killer