To help protect the safety of the City’s drinking water, 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 defined by the Ontario Building Code) to install a backflow prevention 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.

A complete list of sectors required to install a device can be found in Schedule 5 of the Water Supply By-law.