Tree roots are the nemesis of sewer and drain pipes in the Puget Sound area. – especially those installed from the early 1900’s through the 1970’s. The Puget Sound area is full of trees and other greenery creating more issues from roots than many other areas of the country. With sewer pipes installed up until the early 1980’s being predominantly made of concrete and clay (PVC became the most frequent material installed in 1983), root damage is a real concern.
Once roots have infiltrated the pipe, they will continue to grow in diameter. This further creates or worsens gaps in the pipes. In severe cases, roots will completely break the pipe apart or crush it - both of which require that section of pipe to be replaced.
Even before the intrusion is significant enough to break the pipe entirely, the roots will still likely obstruct the flow of water and waste in the pipe causing the backups in showers, toilets and other fixtures. This is generally when we become aware of any of the problems mentioned above.
Cutting roots from sewers to provide temporary relief (from a few months to a few years), but the only way to prevent roots from further growing into a sewer once they have begun is pipe replacement or pipe lining. Removal of the tree(s) that have the damaging roots may not solve the problem completely unless the stump is fully removed and cannot grow anymore. Only after the food supply is no longer available to the tree will the roots stop growing. How long this takes can be dependent on the species of tree and how completely it is removed. If you see new sprouts on a stump, it might not be dead.
The photo shows a 28’ 5” root removed from a 4” diameter concrete storm drain in Renton, WA. The pipe was 100% blocked. You can also see a bell and spigot joint still around the root.