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The Complete Guide to Sewer Backups: Causes & Fixes

The sewage system may not be the most appealing feature of your property, but it is one of the most essential! The network of pipes and drains through which wastewater and solid waste leave your home and enter the main sewer is vital to your health and comfort. 


A common sewage network problem is a sewer backup. This is when some type of blockage prevents the flow of drainage material into the main sewer. Here we consider in more detail the causes and symptoms of sewer backups, as well as how best to fix the issue and prevent it from happening again.

Causes of a Sewer Backup


Sewer Pipe Condition


Over time, sewage pipes inevitably start to deteriorate. Some of the variables that accelerate pipe wear include:


  • Weathering due to daily and seasonal temperature changes in the soil surrounding the pipe.
  • Changes to the soil volume and consistency surrounding the pipe.
  • Subsidence or soil movement causes a change in the gradient or direction of the pipe.
  • Erosion as a result of the action of tree or shrub roots.
  • Animal activity.
  • Pressure, vibration, or other stress due to work carried out in the property or soil surrounding the pipe – building an extension, for example, or landscaping projects, may all cause damaging stresses to be applied.


The pipe’s interior may also wear more rapidly if unsuitable or high volumes of waste are disposed of over time. Chemicals or hard, sharp-edged items can cause damage to the pipe liner, eventually resulting in roughness, cracks, or even an area where the pipe is worn through completely.


Reduced Flow Speed


Unevenness in the sewer pipe lining and/or a change in gradient may reduce the rate at which wastewater progresses to the sewer. Any part of the pipe where wastewater speed is lowered is at risk of deposition. There will be insufficient force to carry larger particles down to the main sewer, and they will be deposited in the pipe that transports waste between your home and the sewer.


Once deposition has started, the deposited particles slow flow more, further increasing the deposition rate and beginning the process of creating a blockage. 


Keeping your sewer pipes in good condition is one of the best ways to reduce the likelihood of a sewer backup.


Increased Volume of Waste


Older properties will have sewer pipes that were designed with the needs of a bygone age in mind. Most people tend to shower and launder more frequently than in previous decades. In addition, we live in a throwaway society, so it’s common for higher volumes of waste food, excess paint, grease, or other unsuitable items to enter the sewage system.


An increased volume of waste may overwhelm the sewer pipe’s capacity, increasing the risk of a blockage.

Organic Blockages


There are typically two types of blockages – organic and inorganic. Organic blockages tend to be caused by a build-up of hair, human waste, food scraps, or fat in the sewage pipe. In most cases, this is due to poor practice in waste disposal. Tree roots and dead animals may both occasionally cause an organic blockage. 


Inorganic Blockages


Again, usually due to poor waste disposal practices, a frequent cause of an inorganic blockage is a toy being flushed down the toilet by curious children. 


Other causes of inorganic blockages include paint, chemicals, or viscous substances (such as varnish, liquid cement, or plaster) being poured down the drain.


Sewer Main Backup


Infrequently, a fault in the main sewer will cause a sewer main backup that affects your property and the properties of your neighbors that share the pipe. 

Diagnosing & Fixing Sewer Back Ups 


The symptoms of blocked sewer pipes are fairly unmistakable:


  • Slow draining or non-draining sinks, showers, and baths.
  • A toilet with a water level that doesn’t return to normal after flushing.
  • Waste not leaving the toilet bowl or even filling the toilet bowl from the sewer pipe.
  • A foul odor.
  • A puddle or damp patch outside that doesn’t clear, even in dry weather.

Diagnose the Cause


Whether you intend to tackle the blockage yourself or use a professional sewer backup cleaning company to get the job done, discovering what’s caused the blockage is the first step towards clearing it.


Many DIY drain clearing techniques use ingredients such as hot water, baking soda and vinegar, or a chemical drain cleaner – if the blockage is inorganic, none of these are likely to make much difference.


If there’s no obvious cause, you may waste valuable time trying DIY interventions that won’t work due to the nature of the blockage. A professional drain cleaning company can save you time and inconvenience by using a cable-mounted CCTV camera to determine the type and location of the sewer blockage accurately.

DIY Sewer Clearance Techniques


A Drain Snake


This is a tightly wound, flexible metal spiral that can be fed into the drainpipe (or through the toilet) using a rotational movement interspersed with back-and-forth movements. The end of the drain snake is hooked, which helps it either latch onto a blockage so that it can be pulled out of the pipe or pushed into a blockage to break it up.


A Plunger


Applying suction may provide enough force to move or disperse the blockage if you’ve got a plunger that will fit snugly over the plug hole of a sink, bath, or shower. 


Depress, then release the plunger initially to build suction, then repeat this movement gently. Remember to cover the sink or bath overflow tightly with a cloth or rag to prevent a loss of suction.


Hot Water and/or Baking Soda and Vinegar 


Occasionally a combination of hot water and/or baking soda and vinegar (which react together to produce carbon dioxide gas) may loosen an organic blockage sufficiently for it to move on down to the main drain.


Store Bought Drain Cleaner


Drain cleaners contain powerful chemicals that dissolve fat and other organic solids. Of limited value for inorganic blockages, drain cleaners should be used with caution. They’re frequently caustic and can harm pets, wildlife, and property occupants if handled, inhaled, or ingested.

Hire a Professional Sewer Clearing Company


If none of the above remedies work, or you prefer a fast, hygienic, safe, and dependable solution for your sewer backup, the professional sewer clearing team from Tornado Plumbing and Drains are the people to call. 


We can offer the following solutions to remedy sewer backups Toronto homes and businesses suffer from:


  • Power flushing/hydro jetting. This involves using a high-pressure water jet to blast the blockage out of your sewer pipe and into the main sewer. Highly effective and fast, hydro jetting leave your sewer pipe clear of all obstructions.
  • Plumber’s plunger. A professional plunger exerts more force than most domestic options. In most cases, it will clear stubborn blockages if they’re located near the entrance to the sewer pipe.
  • Plumber’s drain snake. Similar to a domestic drain snake, our skilled plumbers can often remove smaller blockages with the expert use of a drain snake.
  • Pipe repair and relining. As mentioned, carrying out necessary remedial work on pipes is the best way to prevent repeated blockages.
  • Cable-mounted CCTV. This handy piece of equipment is ideal if you want to find the location and cause of a sewer pipe blockage. Using cable-mounted CCTV is non-invasive. Your plumber can accurately interpret the images, providing high-grade intelligence on the condition of your sewer pipe and information on any blockages.

Preventing Blocked Sewers


Taking proactive steps to prevent a backed-up sewer can significantly reduce the risk of a blockage occurring. Follow these tips to help keep your sewage pipe running freely.


  • If you haven’t had a CCTV survey of your drainage system completed in the past five years, schedule one. The CCTV footage will identify any faults or small blockages so that they can be dealt with before they begin to cause problems.
  • Be careful what you flush down the toilet. Use a waste bin for hair, Q-tips, make-up wipes, tissues, sanitary products, etc. Only human waste and paper should be flushed down the toilet.
  • Install hair traps over your bath and shower plug holes.
  • Install a sink trap to prevent food waste from entering the sewage pipe.
  • Don’t pour grease down the sink! If you own a commercial kitchen, install a grease trap.
  • Make sure that laundry doesn’t have large chunks of dirt or grime adhering to it, as these may be expelled through the laundry drainage pipe into the sewer pipe.
  • Dispose of waste liquids responsibly.
  • Keep the area within a few meters of your drainage pipe free from trees and shrubs.
  • Ensure outside drains have gratings to prevent leaves and other debris from entering the drainage system.


Tornado Plumbing & Drains offers reliable, competitively priced sewer backup solutions. Available 24/7/365, we provide Toronto homes and businesses with fast relief from the misery sewer backups can bring.


Contact the team today at (647) 784 8448.

Serhiy Marynchuk​

Serhiy Marynchuk​

Company owner and lead plumber at Tornado-Plumbing. Serhiy's extensive experience in plumbing as well as leadership skills are some of the reasons the company has been doing well for so many years.​

Serhiy Marynchuk

Company owner and lead plumber at Tornado-Plumbing. Serhiy's extensive experience in plumbing as well as leadership skills are some of the reasons the company has been doing well for so many years.


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