Backflow, in relation to water supply systems, is any unwanted flow of potentially contaminated water into the potable (drinking) water distribution system. This occurs when water flows backwards, or opposite to its normal intended direction of flow, which usually results when water pressure to a property is not maintained or if a pump is connected to a property’s water plumbing system.
Backflow can occur:
- when the water delivery main (reticulation system) is at a lower pressure than a property’s plumbing system - this can occur when there is a burst in the supply main or excessive demand during fire fighting
- if a pump is connected to a property’s internal water plumbing system (that is, a property is using water at a pressure higher than the pressure in a water utility’s supply main)
- with high water usage downstream causing a pressure reduction upstream
- if the water outlet on a property is significantly higher than the water utility’s main with a constant back pressure
- if a bore water supply is connected to a property’s water supply system
Backflow Prevention Devices essentially stop water flowing back into Council’s water mains. The installation of backflow prevention devices on all new and existing residential and commercial water connections significantly reduces the risk of backflow and subsequent contamination of Council’s water supply.
Backflow Prevention Devices must be installed on all new and existing residential and commercial water connections.