Backflow prevention is a term used to refer to the prevention of an unwanted reverse flow of water from a potentially polluted source into the drinking water supply.

Backflow occurs when a condition exists in a water supply system that will cause back-siphonage or back-pressure. The water supply system is designed to ensure your property is supplied with drinking water under pressure. If there is a drop in the supply pressure, there is a risk that water could flow backwards into the water main.

Events leading to backflow:

  • water main pressure is reduced
  • a cross-connection between drinking and non-drinking water exists
  • liquid metals, chemicals, waste or debris enter the drinking water supply by either back-siphonage or back-pressure
  • another property uses the drinking water.

An example of back-siphonage would be a pipeline breakage, undersized pipework or high withdrawal rates. Back-pressure can occur within properties when high pressure is generated downstream by pumps, thermal expansion or elevation.

Examples of potential source of contamination:

  • fire hose reels (FHR)and hydrants
  • irrigation systems
  • swimming pools
  • vehicle maintenance pits
  • ornamental ponds
  • air conditioning towers
  • vehicle/bin washing bays
  • chemical injection areas

Property owners have a responsibility to provide and maintain backflow prevention devices to protect other water consumers from the activities on their property.

More Information

For further specific information, contact the Backflow team on 4688 6108 or backflow@tr.qld.gov.au, or visit your nearest Customer Service Centre.