Backflow Prevention

What is Backflow Prevention work?

Get to know the regulation

Under Part 5 of the Plumbing Regulations 2018, Backflow Prevention work is the repair, alteration, maintenance, testing or commissioning of a backflow prevention device, which is capable of being tested and is listed in Column 1 of Table 4.4.1 of AS/NZS 3500.1.

Typical Backflow Prevention work

Backflow Prevention work protects a property's drinking water supply from contamination that may be caused by backflow. Experienced Backflow prevention plumbers typically do the following work:

  • Selecting appropriate backflow prevention devices
  • Installing and testing backflow prevention devices
  • Maintaining and repairing backflow prevention devices
  • Completing required compliance documentation when the backflow device is commissioned

As a registered practitioner in this class, you must understand and apply the compliance requirements of Backflow Prevention Work. These requirements include the compliance requirements for the parent class of Water Supply work, plus:

  • AS/NZS 2845.1 – Water Supply – Backflow prevention devices
  • AS/NZS 2845.3, Part 3: Field testing and maintenance of testable devices
  • AS/NZS 3500 National plumbing and drainage.

To undertake Backflow Prevention work to a safe and competent standard, you must also be able to:

  • Read a site or building plan and identify water supply lines and locations
  • Identify testing and commissioning requirements
  • Read, interpret and apply manufacturer specifications for installing backflow prevention devices
  • Understand the range of backflow prevention devices available and select those applicable to the hazard rating
  • Perform accurate measurements and calculations and document results of work undertaken.

What do you need to become registered or licenced in this class?


To be eligible to register in this class, you must:

  • Be registered or licenced in the class of Water Supply Work,
  • Have successfully completed the unit Commission and maintain backflow prevention devices (CPCPWT4022A or CPCPWT4022), and
  • Successfully complete the VBA exam for this class.


To be eligible to become licenced in this class, you must be:

  • Licenced in the class of Water Supply Work, and
  • Eligible to hold or currently hold registration in this class.

How to apply

See: Apply for registration in a specialised or restricted class