Backflow prevention

What is backflow?

Backflow can be caused by back-siphonage, when water is siphoned from the property, or back-pressure (for example when a pump is connected to the water supply).  It poses a public health risk because of a cross connection (e.g. chemicals, pesticides, bacteria and industrial waste) that can flow into the drinking water as a result.

What is backflow prevention?

Backflow prevention is the term used to refer to the prevention of an unwanted reverse flow of water from a potentially polluted source into the drinking water supply.

Backflow can be prevented by fitting a backflow prevention device and by ensuring that plumbing systems are correctly designed and operated.

What is a backflow prevention device?

Backflow prevention device’s are designed to protect the drinking water supply (of the town, as well as the premise it’s situated on) from contamination by acting as a barrier, keeping contaminated water separate from the drinking water supply.

Contaminated water incidents may have serious or even fatal consequences for water consumers. By using a backflow prevention device, the unwanted water flow does not enter the drinking water supply; in turn protecting water consumers from drinking or using contaminated water.

Backflow prevention devices are typically installed in the following situations:

  • an irrigation system connected to mains water supply
  • fire hose reels or hydrants
  • a commercial or industrial activity or machinery connected to the mains
  • water outlets in proximity to pollutants, grease traps or chemicals
  • an underground rainwater tank that has mains water backup

Local government responsibilities

In accordance with state legislation, all Queensland local governments must:

  • establish a program for registering each testable backflow prevention device installed at premises in its local government area; and
  • monitor the maintenance and testing of each device; and
  • keep a register containing each notice given to the local government.

Council’s Backflow Prevention Device Register contains information supplied by licensed, backflow endorsed plumbers on submitted Form 9 test reports. Device information is then compiled onto the Backflow Testing Notices issued by Council, as a courtesy to property owners and their chosen plumber.

Information for property owners

> Property owner responsibilities

In accordance with state legislation, the owner of the premises (where a backflow prevention device is installed) are required to:

  • register all testable backflow prevention devices, by giving notice in the approved form (Form 9) to local government (if the licensed, backflow endorsed plumber engaged to carry out the work has not already done so); and
  • have the device maintained and tested at least once each year after registration by a licensed, backflow endorsed plumber.

If the device is not maintained, tested and a Form 9 test report submitted to council by 31 December, the owner of the premise may face penalties for non-compliance with the state legislation requirements.

At the beginning of each calendar year, Council issues a courtesy Backflow Testing Notice to the owner of the property where the device is located, prompting them to arrange for the maintenance and testing of each device of the property by 31 December. A subsequent reminder is also issued once during the year to property owners whose Form 9 test reports have not yet been received. These notices must be passed onto tenants (where applicable) and the licensed, backflow endorsed plumber hired to conduct the work.

Licensed, backflow endorsed plumbers can be found by searching for "backflow plumber Mackay" via an internet search engine.

> Fees and charges

All device installations/registrations incur a registration fee, as per the Schedule of Fees and Charges.

Council issues a Backflow Renewal Notice to the owner of the property were the device is located, in July of each year, prompting payment of the Annual Renewal Fee. The Annual Renewal Fee is charged per device and is used to maintain the Backflow Prevention Device Register, perform audits/investigations, and issue various notices to property owners.

> Removing or replacing a device

If your plumbing changes, you may no longer need a backflow prevention device.

A licensed, backflow endorsed plumber must assess the situation prior to the backflow prevention device being removed. If the plumber confirms there is no longer a risk to the water supply, they may remove the device once the hazard is no longer present and submit the relevant paperwork to Council (Form 9), the QBCC (Form 4) and the property owner (copy of Form 9 and Form 4) within 10 business days.

It is illegal to remove a backflow prevention device without going through this process and any such removal can lead to the imposition of penalties. Council will also not remove a backflow prevention device from the Backflow Prevention Register until a Form 9 and Form 4 can be produced by the licensed plumber who conducted the works. Annual renewal invoices and testing notices will continue to be issued to the property owner until the appropriate documentation can be provided.

Council may audit device removals performed under a Form 4 to ensure the risk to the water supply is no longer present.

Information for plumbers

> Plumber’s responsibilities

In accordance with state legislation; the ‘licensee’ (a licensed, backflow endorsed plumber) who installs, replaces, removes or tests a testable backflow prevention device must, within 10 business days after carrying out the relevant work:

  • give notice of the relevant work in the approved form (Form 9) to the local government and to the owner of the premises.

For works involving the installation, replacement or removal of the backflow prevention device under the notifiable works category; the ‘licensee’ must also, within 10 business days after notifiable work is finished:

  • give the following to the commissioner (QBCC), unless the person has a reasonable excuse -
    (a) a notice, in the approved form (Form 4), about the work; and

    (b) the fee prescribed by regulation for giving the notice.

> Obtaining device information for annual testing

The plumber conducting the work must obtain and utilise the partially pre-filled Form 9 issued by council to the property owner, as the information on the form comes directly out of the Backflow Prevention Device Register and will assist with locating the device.

If they plumber conducting the work is unable to obtain a copy of the partially filled Form 9 from the property owner, you may download a blank copy of the form from the Forms and Guide section below.

Please Note: council is unable to provide copies of the partially pre-filled Form 9 to plumbers. Plumbers must retrieve this document directly from the property owner or utilise the abovementioned blank version.

All completed Form 9 test reports are required to be emailed to for processing, within 10 business days after conducting the works.

If the Form 9 is not submitted to council within 10 business days after conducting the works, the plumber may face penalties for non-compliance with the state legislation requirements.

> Forms and guides

Need more information? Contact council’s Development Support team via email at or via phone on 1300 622 529.