Backflow Prevention

Water Corporation of WA Backflow Prevention Policy requires the installation of an approved backflow prevention device at the boundary of every water service connection to a property (including fire services).

Backflow is a reversal of the normal direction of water flow in a water supply plumbing system. It occurs when the water delivery main is at a lower pressure than the internal plumbing system (back siphonage). Back siphonage can occur when there is a burst or ruptured water main, or due to excessive demand during fire-fighting operations or other periods of high demand.

Backflow can also occur if a water pump, such as a bore pump, is cross connected to the internal water plumbing system, and is pumping bore water at a higher pressure than the water mains pressure (back pressure).

If a property’s drinking water supply is inadvertently connected with a source of pollution, either through a cross connection or simply a hose submerged in a container of liquid, then these pollutants could enter the water supply when there is an overpressure on the private property side or a sudden drop in water mains pressure.