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.
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
- Day care centres and kindergartens
- Pest control and water carrying vehicles
- Botanic gardens
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.
Application and registration of a backflow prevention device
We are required to keep a register as per the following:
- Standard Plumbing and Drainage Regulation 2003 Section 38 – Testable backflow prevention devices
- State Government Standard Plumbing and Drainage Regulation 2003.
- A local government must implement and maintain a program for its local government area for the registration, maintenance and testing of testable backflow prevention devices installed in the area.
- The local government, or an entity authorised by the local government, must keep a register of the testable backflow prevention devices.
- An owner of an installed testable backflow prevention device must-
a) register the device with the local government or entity; and
b) at least once each year, have the device inspected or tested by a person who is licensed to do the work.
- A person who inspects or tests a testable backflow prevention device must, within 10 business days after inspecting or testing the device, give the local government written results of the inspection or test.
Testable backflow devices require annual testing and are registered by Council. When submitting annual test reports, please post to The Chief Executive officer, PO Box 3021, Toowoomba, Qld 4350. A person who inspects or tests a backflow prevention device, must within 10 business days after inspecting or testing the device give Council written results of the inspection or test.
An application to install a testable backflow prevention device is to be made to councils plumbing section, please contact council.