Backflow prevention

Backflow prevention refers to the control of potentially harmful contaminants entering into our drinking water supply from cross connections in a customer’s premises or backflow of contaminants into the water supply system.

Requirements and responsibilities

Backflow prevention devices are required under our Site Containment Backflow Prevention Standard, Australian Standards AS/NZS 2845: Water Supply – Backflow Prevention and AS/NZS 3500: Plumbing and Drainage for any property or operations that pose a risk to the public drinking water supply.

The risk assessment process

All properties connected to our water supply system are required to be risk assessed and have an applicable site containment backflow prevention device installed. The risk assessment should address the requirements of our Site Containment Backflow Prevention Standard to determine if the property is a high, medium or low hazard risk to the drinking water supply.

If the property operations are outside the scope of the Standard contact our Technical Services team.

Resources

Frequently asked questions

Learn more about hazard ratings, required devices, and a customer's right to appeal the rating.

  • What are the hazard ratings?

    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.
  • What device is required for each hazard rating?

    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.
  • What are the risk ratings?

    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.

  • Can a customer appeal a backflow risk 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

Lodge a backflow test report

If you are an accredited backflow compliance plumber, you can submit device certification using our online system.

Thirsty for more advice?

If you need more advice on backflow prevention devices, installation, testing or accreditation, get your questions answered by contacting our team.