Drain Pipe Blockage: Getting to the Root of the Problem


The thing about tree roots blocking drainage pipes is that it all happens far out of sight. If one problem is not being able to see the forest for the trees, another is not being able to see the roots for the ground.

Roots know their business: finding and feeding nutrients to the tree they support. Do do this, roots are active in seeking out water, and any crack or open joint in underground piping is an invitation to roots to grow into the pipe. As an added bonus, drain piping, filled as it is with food waste, oils, fats, and other debris, provides a rich source of just the nutrients that roots seek.

Tree Root Removal


Roots are extremely powerful: while they might move slowly, they are able to heave cement and slit rock, given a foothold. That’s what they do. The continually thickening roots, when they encounter a way into a pipe, enter with thin filaments that can develop into a mass sufficient to clog a pipe. As roots thicken, they can split pipe as well.

Some sorts of piping are more prone to root blockage than others; clay piping is more easily penetrated and has more joints than other materials, such as concrete piping and PVC piping.

Certain types for foliage and trees are also more likely to cause problems than others. Water-loving trees, such as willows, are just the sort of plant whose roots can damage piping and even building foundations. Clemson University’s excellent paper “Tree Roots and Sewer Line Intrusion” offers lots of detail.


In some cases, roots that are blocking a pipe can be removed using a cutting tool that passes along the inside of the pipe, when the walls of the pipe are thick enough that the cutter will not penetrate the pipe wall itself. However, cutting away invading roots that have already entered the pipe is a stopgap measure at best. By that point the pipe has already been compromised, and removing the roots inside the pipe will neither repair the damaged pipe nor stop the root growth starting up just where it left off.

Repair of drainage systems invaded by root masses can be costly, but there is no alternative. Left alone, the root mass will only grow larger and more dense, obstructing and eventually blocking pipes. One sign that a drain pipe is plugged is that multiple fixtures all back up: the problem is not localized to the plumbing closest to any given fixture.

The most effective solution to root blockage is to remove the roots entirely. This work involves excavating to expose the pipe, removing any roots causing problems, replacing damaged pipe with a well-sealed replacement, and closing the excavation.

Preventative maintenance is also wise, either before root blockage has become a problem, or after a removal and repair operation. Trees should be kept away from piping routes.

What help will the City of Toronto provide to solve root blockages? Unfortunately, not much. The City takes the position that roots are not the cause of the problem, a viewpoint that seems at odds with lived experience. Technically, perhaps, because roots will not break into sealed pipes in a search for water, that position is true. However, pipes do crack and joints are not always perfect, so the combination of piping imperfections and thirsty roots does lead to problems.

In addition to water, roots need air, so root systems will stay almost exclusively in the upper two or three feet of soil. That is, until there is pipe leakage. At that point, roots will descend deep into the soil and get into already-cracked pipe.

The City of Toronto will therefore not approve the removal of trees due to drain and / or sewer blockages, and approval to remove trees can be time-consuming and costly. The upside is that a plumbing contractor familiar with the ins and outs of the city’s rebate programs may still find an applicable means of obtaining support. The City of Mississauga also has information on residential plumbing matters and rebate programs for downspout disconnection and sanitary backwater valve installation that might be of use.

When looking for a solution to plumbing problems caused by root infiltration, expertise matters. The experienced professionals at Master Drain will help you find your way out of the forest of roots.

Master Drain