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Backflow prevention – RPZ Valves

March 26th, 2019

Sydney Water has very strict regulations regarding the drinking water supply, for the health and safety of the public. Backflow Prevention is a very important part of these regulations. Backflow prevention devices are used to protect potable (or drinkable) water supplies from contamination or pollution due to backflow.


What is Backflow and how can it be prevented?

Backflow is the unwanted reversal of the flow of a liquid, gas or a solid into the drinking water supply. Imagine when you drink through a straw, pressure in the straw is reduced as you draw up the fluid through the straw into your mouth to drink it. When you let go of the straw a back siphonage occurs where a drop in pressure causes the liquid to be drawn back down into the cup possibly bringing undesirable things back down with it. On the other hand, just as air bubbles can be blown through a liquid to the surface, gas bubbles could also be pushed through the water supply system. Backflow preventers are installed at potential points of contamination to prevent the potable water supply from being polluted with these undesirable materials. These backflow preventers are commonly known as RPZ valves or Backflow Prevention Devices.

We are so lucky to have easy access to fresh and clean water supplies on a daily basis, and the amazing thing is backflow prevention devices are made with an ingenuity that can be traced back to ancient times such as the Roman Empire where engineering genius and the skills of early plumbers were applied to erect the great baths and recreation centres of the times.


Where do you find RPZ Valves?

Backflow Prevention Devices are generally built in to standard water meters. Separate backflow devices are required for larger water meters or for sites that have been labelled as having a medium or high hazard rating for backflow. Commonly, schools, shops and industrial worksites have separate backflow devices installed to prevent water cross contamination. Sydney Water monitors these devices and it is a legal requirement that these sites are required to have their devices tested yearly by a licensed plumber with a Backflow Prevention Accreditation. The Plumber then files a report back to Sydney Water following the testing.


We are licensed to install backflow prevention devices!

At TASM Plumbing, we have always been licensed to install these devices however up until this point, we have not been licensed to undertake the commissioning, testing and annual retesting of the devices.

We now have this accreditation under our belt. So if you have a device that is legally required to be commissioned or tested annually (Sydney Water will let you know if you do), give us a call.

We service all areas of the Illawarra – in and around Kiama, Shellharbour and Wollongong and through to Bulli. We will ensure that your paperwork is submitted to Sydney Water immediately, with the fairest pricing as well. We are friendly, fast and reliable in our work so give us a call for all your plumbing needs, especially backflow prevention testing!


sydney water accredited plumber