Backflow prevention
What is backflow?
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.
Backflow can be caused by back-siphonage, when water is siphoned from the property, or back-pressure, for example when a pump is connected to the water supply. It poses a public health risk because of a cross connection (e.g. chemicals, pesticides, bacteria and industrial waste) that can flow into the drinking water as a result.
How can backflow be prevented?
Backflow can be prevented by fitting a backflow prevention device and by ensuring that plumbing systems are correctly designed and operated. A backflow prevention device prevents the unwanted reverse flow of water from a potentially polluted source into the drinking water supply. Cross-connections should be avoided wherever possible, but where they exist they must be fitted with backflow prevention devices.
What are my responsibilities?
Install backflow prevention devices for specified equipment as identified in legislation (e.g. fire hose reels, water tanks, irrigation systems, pools etc.). Under Government legislation, testable backflow prevention devices must be:
- Registered with Mackay Regional Council
- Tested annually by certified trades people (download the Backflow Prevention Device Testing Form (PDF 38.0KB) (Form 9 equivalent) to test new devices)
Properly designed, installed and maintained plumbing systems will ensure protection of our drinking water supply.
Testing of backflow devices can be done by any plumber licensed to test backflow devices. Refer to your local phone directory for contact details.
Examples of a potential source of contamination
- Fire Hose Reels (FHR)
- Irrigation
- Swimming pools
- Vehicle maintenance pits
- Ornamental ponds
- Air conditioning towers
- Vehicle/bin washing bays
- Chemical injection areas
- Rainwater tanks
Examples of properties requiring backflow prevention
- Motels and unit complexes
- Hotels
- Some residential houses
- Some industrial premises
- Vehicle repair workshops
- Shops
- Restaurants
- Caravan parks
- Medical and dental surgeries
- Car and plant washing facilities
- Dry cleaners and laundries
- Hospitals and funeral parlours
- Club houses for sports
- Schools
- Day care centres and kindergartens
- Pest control and water carrying vehicles
- Botanic gardens
Backflow prevention devices
The backflow prevention device will have either a brass or a stainless steel casing and will also have 2 or 3 test cocks.
Pressure vacuum breakers (pictured below) have 2 test cocks and are for a low hazard rating.
Double check valves (pictured below) have 3 test cocks and are for a medium hazard rating.
Reduced Pressure Zone (pictured below) will have 3 test cocks and in addition have a dumping port and are for a high hazard rating.
