Sewers and tree roots
Property owners are responsible for maintaining sewer lines from a building or private residence to where it joins the main line. Sewer lines should be kept in good repair, properly maintained and regularly cleaned. This is especially important in older structures where tree roots often gain entry to sewer pipes through cracked portions of the pipe, causing blockages.
About trees, tree roots and sewer pipes
- Roots from trees growing near sewer lines do not actively penetrate sewer pipes and cause blockages.
- Roots gain entry through previously cracked portions of sewer pipes.
- Sewer pipes inevitably deteriorate through old age or separate and crack due to ground shifting and heaving.
- Sewer pipe is laid approximately 2 metres, or more, deep.
- The only tree roots at that depth are anchor roots, as the finer and fibrous feeder roots are located within the first metre of soil.
- Anchor roots can co-exist with intact sewer pipes indefinitely without causing blockages.
- A sewer line leak allows sewage and air to escape into the soil, creating a ratio of air, water and nutrients at that depth that becomes similar to those found near the surface. Anchor roots at the site of the leak produce very fine, opportunistic feeder roots that can enter the sewer pipe.
In situations where the property owner requests (in writing) the removal of publicly owned trees for the reason of sewer line blockage, a representative of the Forestry Branch will inspect the tree(s) and make a decision in this regard. Publicly owned trees are not normally removed for the reason of sewer line blockage. Healthy trees are a valuable asset to the community and the City and are only removed when they are dead, diseased, dying, involved in approved construction or are hazardous in terms of safety or visibility.