What is backflow prevention?
Backflow prevention is the term used to refer to the prevention of an unwanted reverse flow of water from a potentially polluted source into the drinking water supply.
Application and registration of a backflow prevention device
Backflow prevention devices can be installed to eliminate the risk of contamination. Application and registration of a backflow prevention device is managed by your local council. For more information, please contact:
Moreton Bay Regional Council
Sunshine Coast Council
When does backflow occur?
Backflow occurs because a condition exists in a water supply system that will cause back-siphonage or back-pressure. Back-siphonage can occur on a property through a vacuum created in the water supply system.
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.
Backflow prevention starts within a property boundary by isolating a possible contamination source from the town mains or storage tanks (rainwater tanks) from the tap or appliance.
Examples of potential source of contamination:
- fire hose reels (FHR)
- swimming pools
- vehicle-maintenance pits
- ornamental ponds
- air-conditioning towers
- vehicle/bin-washing bays
- chemical injection areas.
Examples of properties requiring backflow prevention:
- motels and unit complexes
- vehicle-repair workshops
- caravan parks
- medical and dental surgeries
- car and plant-washing facilities
- dry-cleaners and laundries
- hospitals and funeral parlours
- club houses for sports
- daycare centres and kindergartens
- pest control and water-carrying vehicles
- botanic gardens.
What is the safeguard to prevent a backflow occurrence?
A correctly selected backflow prevention device (one-way valve) will eliminate any risk of contamination of the drinking water supply. Backflow devices are either testable or non-testable types with the selection dependent on the risk associated with the possible contamination.
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