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Backflow Prevention - Determining which device to install
Determining which device to install
The customer should be aware of the type of device, which needs to be installed. If your plumber installs the incorrect device then the property may not comply with Sydney Water's requirements. This could mean an additional cost to you to install the correct device.
You may already have backflow prevention devices installed within the property. A containment backflow prevention device is required regardless of zone or individual protection. As Sydney Water cannot guarantee the integrity of zone or individual protection on a customer's site, we cannot guarantee the protection of the drinking water supply from backflow unless the site is contained.
The device to be installed on the property is determined by the hazard rating of the processes on site. If the hazard rating varies due to multiple processes, the highest hazard rating will be applied. A list of devices and their relevant hazard rating is below.
The cost of installation and ongoing maintenance including the annual test cost is a matter to be negotiated between the owner and the occupier.
Installation prices vary according to the size of your water meters and site conditions
Types of backflow prevention containment devices
Hazard rating: High
Reduced Pressure Zone Device
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Two independent action non-return valves arranged to be force-loaded to the closed position with a relief valve positioned between the non-return valves arranged to be force-loaded to open to atmosphere.
Hazard rating: High
Registered break
tank/Registered air gap
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The unobstructed vertical distance through the free atmosphere between the lowest opening of a water service pipe or fixed outlet supply water to a fixture or receptacle and the highest possible water level of such fixture or receptacle.
Hazard rating: Medium
Testable double check valve
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Two independent action non-return valves arranged to be force-loaded to the closed position fitted with three test taps for annual testing.