What is backflow (plumbing)?

Backflow is when water flow comes back into your plumbing system the opposite way it’s supposed to. This is caused by a drop in pressure from the mains to your internal plumbing system, known as water siphonage.

How do you prevent Backflow?

A backflow prevention device should be installed between your main supply and internal plumbing system. This essentially stops contamination of your water supply by controlling the pressure. It ensures the clean water supply and the used (water waste) does not cross over. Put simply, it stops the water from your waste or from the main sewer lines from ever reversing back into your (or others) drinking water system.

Backflow system

How do I know if I need a backflow device?

Everyone is required to have a backflow device to prevent contamination. You can be risk assessed to determine whether you need to register it and make annual checks. You usually apply for a backflow device if you are a:

  • new development
  • redevelopments of existing facilities
  • changing any existing water service
  • additions and alterations (includes where no water service applications are included, applicable only if the property has existing meters)
  • multiple residence and/or commercial –  (This includes where no water service applications are included. Applicable only if the property has existing meters)
  • any applications that involve a fire service
  • any applications where the minimum water service size applied is greater than 25mm in size. (Except fire services, where the backflow advice applies regardless of the service size)

It is the owner’s responsibility to ensure you have a backflow device installed. If you don’t have a backflow system then you should talk to your builder and water corporation to determine your next steps.

Do you require backflow maintenance?

If you meet the risk required for a registered device, It’s mandatory to have it tested by an Australian licensed plumber annually, and must be registered if it is installed in the boundary line. A risk assessment is completed on installation which would decide the risk level of your properties backflow and if registered as a medium or high risk building the test results must be submitted to the water corporation no more than 5 days after having the check which should take place no more than 12 months from your last check.

Backflow testing is where a qualified plumber checks the pressure and flow of your water supply system. They are also checking for water contamination. So even if your property is residential it’s always good to have the test done to ensure your water is not contaminated.

How can you tell if the water is contaminated?

It is often hard to tell when your water is contaminated as it can be odourless, colourless, and tasteless.

That’s why it’s important that each year you should have your facilities’ water supply checked by the required date. At Mathiou Services we are qualified and trained to carry out backflow testing with scheduled maintenance every year to meet these regulations.

If you require this test feel free to contact us on 1300 363 423.