Backflow Prevention

Plumbers are responsible for registering site containment backflow prevention device testing certification with us.

We register site containment devices only. Zone and individual devices still require testing but are not managed by us.

Where a device has failed, the property owner is required to arrange to have the device repaired or replaced and retested, with the device certification registered with us.

When does a site need backflow containment?

Backflow prevention devices are an important component in protecting the Lower Hunter's drinking water. They are required under our Site Containment Backflow Prevention Standard, Australian Standards AS 2845: Water Supply – Backflow Prevention and AS/NZS 3500: Plumbing and Drainage, for any premises that pose a risk to the public drinking water supply.

Which backflow device should you install?

The type of device that should be installed depends on the hazard rating of the processes carried out at the property.

The three hazard ratings identified by AS/NZS 3500:1 are:

  • High hazard – any conditions, device or practice that are connected to the water supply system and have the potential to cause death.
  • Medium hazard – any conditions, device or practice which in connection with the water supply system could endanger health.
  • Low hazard – any conditions, device or practice which in connection with the water supply system would constitute a nuisance but not endanger health.

Residential, commercial and industrial properties that have been categorised as medium or high hazard (and low hazard above 25mm) are required to have an approved, testable backflow prevention device installed at the outlet of the water meter.

If the process at a property changes and the hazard rating is increased, the property owner must have a licenced and backflow accredited plumber certify the change in hazard rating and inform Hunter Water. A high hazard rated site containment backflow prevention device may be required to be installed.

How to install a backflow device

The licensed plumber is required to do a risk assessment of the hazards at the property using Hunter Water’s Site Containment Backflow Prevention Standard. If outside the scope of the Standard, contact Hunter Water at

The licensed plumber shall install the applicable backflow prevention device to comply with Australian Standard AS2845 requirements. An accredited backflow tester is required to commission and certify the device within seven days of installation, and submit the online test report to us.

How to become an accredited backflow tester

We only recognise accredited backflow testers to submit device certification.

To be accredited with us for backflow prevention testing, you are required to:       

  1. Be a current licensed plumbing contractor with NSW Fair Trading.
  2. Submit your TAFE backflow accreditation certificate to
  3. Hold current and adequate levels of workers compensation, public liability, product liability.

Once accredited, you are eligible to access and submit device certification via our online system below.

How to lodge a test report

Once the backflow prevention device has been tested:            

View our Backflow Application Terms and Conditions and Electronic Business Terms of Use