Every year, thousands of people suffer from sickness due to contaminated local water supply, as well as burns and scaling due to high water temperatures. A major cause of such water-based sicknesses and injuries are due to water supply systems that have no or untested backflow prevention devices, and tempering valves or thermostatic mixing valves (TMVs) not being installed or tested.

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Backflow prevention

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'Backflow' is essentially the reverse flow of water from a potentially polluted water source into your drinkable water supply. Backflow prevention devices are required to be installed onto your plumbing system to help protect both drinking water and the mains water supply from contamination or pollution where there is a risk of backflow occurring. As such, it is extremely important that your backflow devices are installed correctly and are maintained regularly.

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Testable backflow devices include:

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• Reduced pressure zone device (RPZD) 

• Double check valve (DCV)

• Single test valve testable (SCVT)

• Registered air gap (RAG)

• Registered break tank (RBT)

• Pressure vacuum breaker (PVB).

 

In accordance with the Australian Standards (AS 2845.3), testable backflow devices must be registered with the local council and tested at least once every 12 months by a licensed plumber with a backflow prevention endorsement. A written copy of the test report (Form 9 - Registration & report on inspection and testing of backflow prevention devices, registered air gaps and registered break tank) must be submitted to the local council within 10 business days of testing.

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Your local council will contact you each year requesting each device’s Form 9 and the applicable annual registration fees. Failure to keep up with your annual testing obligations could allow preventable contamination and health risks to occur, and heavy fines can be imposed. 

 

If a device fails upon testing, the maintenance/repair of the device must be carried out immediately to ensure there is no risk of backflow occurring. If the device cannot be repaired at the time, the affected section of the water supply system is required to be shut down until such time that the device can be repaired or replaced, and re-tested achieving a pass result. 

 

​Whilst most common in commercial settings, some residences may also require a backflow prevention device.  Potential sources of contamination include:

 

• Air conditioning towers

• Irrigation areas

• Fire systems (hose reels/hydrants/sprinklers)

• Swimming pools and spas

• Vehicle maintenance pits

• Dishwasher/glass washer

• Vehicle washing bays

• Sullage pits/process tanks

• Chemical injection areas

• Boilers/steam pipes

• Dockside facilities/jetties

• Bidets.

 

Mountain Tides Plumbing can install, repair, maintain and certify all kinds of backflow prevention devices. Call us today!

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Thermostatic mixing valves (TMVs)

 

A TMV is used to blend hot and cold water, ensuring hot water temperatures are at safe levels when delivered to a faucet. Whilst similar in function to tempering valves, which are typically used in residential homes, TMVs are generally used in environments that include high-risk persons (e.g., children and the elderly) that require a lower water delivery temperature. This is mainly due to TMVs being more accurate in temperature control, with an approximate accuracy of 1°C +/- (compared to  3°C +/- for tempering valves).

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In accordance with the Australian Standards (AS 4032.3), TMVs are required to be inspected, tested and maintained every 12 months (at a minimum), with the replacement of temperature-sensitive actuators and other critical components (i.e., o-rings) taking place every 5 years (unless required sooner). TMV testing must be undertaken by a licensed plumber with a TMV endorsement. 

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If a TMV is not functioning in accordance with its intended application, maintenance is required to be undertaken to rectify the issue, or alternatively, the device must be replaced. 

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Mountain Tides Plumbing can provide regular servicing and testing for your TMVs, ensuring they're functioning correctly for the safe delivery of hot water. As part of our services, we'll provide you with a detailed service log sheet for on-site record-keeping, which includes:

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• The model, manufacturer and identification of the valve

• Location of the valve

• Temperatures recorded during the test

• Details of tests, maintenance and parts replaced.

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