Backflow prevention

The three 'cross connection' hazard ratings identified by Australian Standard AS/NZS 3500 Plumbing & Drainage are:

• Low hazard – any condition, device, or practice that in connection with the water supply system, constitutes a nuisance but does not endanger health or cause injury.
• Medium hazard – any condition, device, or practice that in connection with the water supply system, has the potential to endanger health.
• High hazard – any condition, device, or practice that in connection with the water supply system, has the potential to cause death.

The hazard rating of the site's operations and processes determines which type of device you are required to install. If the hazard rating varies due to multiple processes, you must apply the highest hazard rating.

• Low hazard – All 20mm and 25mm Hunter Water issued water meters incorporate internal low hazard devices therefore no additional device is required in this instance. We manage the replacement of these devices through our meter exchange program. For water meter sizes greater than 25mm, an independent site containment testable device is required to be installed immediately downstream of the property’s water meter.
• Medium hazard – An independent testable back flow prevention device is required for all service sizes. We recognise a testable Double Check Valve (DCV) for this category. The device is to be installed immediately downstream of the property’s water meter.
• High hazard – An independent testable back flow prevention device is required for all service sizes. We recognises a testable Reduced Pressure Zone Device (RPZD) for this category. The device is to be installed immediately downstream of the property’s water meter.

Backflow risk can be classed as low, medium or high as provided in our Site Containment Backflow Prevention Standard and Australian Standard AS/NZS 3500 Plumbing & Drainage.

• Low risk – any condition, device or practice in connection with the drinking water supply system that constitutes a nuisance but does not endanger health or cause injury.
• Medium risk – any condition, device or practice in connection with the drinking water supply system that could endanger health.
• High risk – any condition, device or practice in connection with the drinking water supply system that could cause death.

The hazard rating of the site's operations and processes determines which type of device you are required to install. If the hazard rating varies due to multiple processes, you must apply the highest hazard rating.

Yes. If the property owner considers the risk rating assigned to the property is higher than the risk of site-specific activities being carried out, then they may appeal this rating.

The appeal must include:

• reason for proposed risk downgrade from a licensed plumber (include supporting evidence)
• You licence number, name and contact number

A formal appeal can be submitted to our Technical Services Section via email