A backflow preventer is a device used to protect water supply systems from contamination or pollution. It is designed to prevent the reverse flow of water, which can occur when there is a drop in pressure in the water supply system. This drop in pressure can cause contaminated water from a non-potable source to flow back into the clean water supply.
Backflow preventers are commonly used in plumbing systems, irrigation systems, and other water supply systems to ensure the safety and quality of the water. They work by automatically closing off the water supply when a reverse flow is detected, preventing any contamination from entering the system.
There are different types of backflow preventers available, including pressure vacuum breakers, double check valves, and reduced pressure zone assemblies. The specific type of backflow preventer required depends on the level of hazard and the local plumbing codes and regulations.
It is recommended to have backflow preventers installed and regularly maintained by qualified professionals to ensure the continued protection of the water supply system.
You can check the rules at City of Toronto website
City of Markham