backflow preventer

How a Backflow Preventer Works

backflow preventer testingClean and non-contaminated drinking water is something that many Canadians take for granted. However, over the years there have been several incidents that contaminated water has caused illnesses and deaths. Understanding how a backflow preventer device works and the regulations in your City are crucial.

What is backflow?

Backflow refers to the unwanted reversal of the flow of water into the potable (drinking) water system and is caused by pressure changes. This reversal can lead to harmful chemicals being pulled into the drinking water supply. A backflow preventer stops this process.

When can backflow occur?

There are two conditions where pressure changes can contribute to the reversal of flow:

Backsiphonage: This happens when there is a negative pressure in the supply piping, allowing downstream substances to be siphoned back into the potable water supply. Under-sized pipes, pipeline breaks, and high withdrawal rates can create vacuums, which contribute to the occurrence of backsiphonage.

Backpressure: This happens when the flow pressure downstream is higher than the supply, allowing downstream substances to be pushed into the potable water supply. This can be created by pumps, thermal expansion and elevation.

backflow preventer installation and testing
backflow preventer installation and testing

SIMPLY a backflow preventer keeps drinking water safe from contaminates.

For a more in depth article on how these devices work click here.

What type of backflow preventer should be used?

Backflow prevention devices and assemblies include:

  • Atmospheric Vacuum Breakers
  • Dual Check Valves
  • Pressure Vacuum Breakers
  • Double Check Valve Assemblies
  • Reduced Pressure Principle Backflow Assemblies

The proper selection of a backflow preventer is crucial and needs to be selected by a CCC (Cross Control Certified) plumber.

Avoid Contamination –

Certified Backflow Prevention Installation & Testing Toronto

backflow prevention installation and Testing Specialists

What are the backflow regulations in Toronto?

It is mandatory under the City of Toronto’s Water Supply By-law for property owners of industrial, commercial, institutional and Part 3 residential properties, as well as construction sites, to install a backflow preventer device on the water supply line(s) to their facility. This is done to isolate buildings from the City’s water distribution system, helping to ensure contaminants do not enter drinking water.

These devices must be tested yearly by a licensed plumber who is Cross Control Certified.

More information can be found the on the City of Toronto website here.


Trouble Shooters is an approved contractor for the testing, installation, and maintenance of commercial backflow preventers. Call us today to learn more or set up your appointment!

Contact Trouble Shooters for professional plumbing service in Toronto and Scarborough