Backflow Device Testing

by Gilbert J Donald

A lot of people wonder if there really is a need for backflow prevention and for annual backflow prevention device testing – the answer is stern “yes”. Here is a look at what the device is and what it does, and why it is important. 

What is a backflow prevention device?

A DCV (which is a double check valve) or a PRZ (which is a reduced pressure zone) are used to protect your water supply from becoming contaminated or polluted because of backflow. The valve is installed on the pipes to protect your drinking water and the water of others.

A few examples of why you need this device

There are a lot of situations where a backflow prevention device will protect your water source, but here are a couple to drive the point home.

  1. If you have a hot tub or a swimming pool – When there is evaporation you likely top up the water level using a garden hose. Just put the hose in the spa or pool and then turn on the hose tap. Nothing wrong with this right? Well, that depends on whether or not a backflow prevention device is installed or not. What if while you are filling the pool and doing other things, the fire department has to come to a house in the neighbourhood and use a fire hydrant to put out a fire. The use of the hydrant will cause a pressure drop in the water and your hose in the pool will, instead of putting water in, start sucking water out. It will go into the hose and back into the public drink water system. People can get sick and even die when drinking water that is contaminated. With a device and yearly backflow testing Perth, you can prevent the backflow of pool water into the potable drinking water source.
  2. If you have sprinklers for watering your lawn – You might use fertiliser and chemicals on your lawn to control weeds and help the grass grow. If a couple or even just one of the sprinkler heads does not sit properly below the ground, water will pool around the head. This can contaminate the water because of the lawn and soil. Now a few blocks away the water main breaks and people lose water pressure. This causes suction and the sprinkler heads draw in those contaminated pools of water into the drinking water system. With backflow prevention device testing on a regular basis, this can be prevented.


Annual backflow device testing is a legal requirement. Plumbing experts come in and make sure the device is working as it is meant to and that no contaminated water is entering the public drink water system. Even when devices are well made and correctly installed, things can fail, wear down and so on. With regular testing, you can ensure backflow prevention can protect your water source and the health of people living and working around you too.


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