Installing Backflow Prevention Devices for Plumbed-in Rainwater Tanks

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Installing Backflow Prevention Devices for Plumbed-in Rainwater Tanks

When plumbing in a rainwater tank, a typical setup is to connect mains water to it as a backup water supply. When your tank runs dry, a rainwater to mains water switch can flip over to your mains water so that toilets and washing can continue without issue.

Connecting to your mains water supply means a licensed plumber needs to install an approved backflow prevention device. This article covers what a backflow prevention device is and why they are important to install.

What is Backflow?

When connecting to your mains water supply, we normally think that the water goes one way through the pipes to our properties. Backflow occurs when water travels the other way, from a property backwards into the pipes of the mains water supply.

Water flowing back into the mains water grid can occur if:

  • there is a drop in the pressure of your mains water supply, for example during a main break.
  • water pressure on the property is higher than at the main, for example water pumps that are in operation to pump rainwater from your tank into your home.

Why is Backflow Prevention Important?

We expect our local councils and water authorities to ensure the water they provide to our properties is safe for drinking, therefore it is important they ensure no water flows backward into the water grid that carries contaminants that could harm our health and the health of others.

There are many ways contaminants that can find their way into your water supply. Cross connections are a common issue, unauthorised plumbing connections between two water sources that should be separate, for example drinking water, recycled water and wastewater systems. They are caused by bad plumbing or even hoses submerged in buckets, tanks or swimming pools.

Contaminants such as chemicals, oil, bacteria, mud and debris must obviously be prevented from finding their way into the water grid for safety reasons, since many depend upon such for drinking and cooking.

Water Backflow Prevention Devices

So, how do you stop water from flowing backwards from your property? The solution is a backflow prevention device which stops water flowing back into a pipe. Backflow prevention devices work in one of the following ways to stop water flowing backwards:

  • a valve that only lets water flow in one direction
  • an air gap below the water coming out (for example, water can flow out from tap into a sink, but not from a sink back up into a tap)
  • a break tank, which is a pressureless and closed water tank, with an air gap that ensures zero backflow into the system.

Responsibility for Backflow Devices

Property owners are responsible for ensuring that the right kind of backflow device is installed. While a licensed plumber accredited to install backflow prevention devices must install them, the property owner is responsible for ensuring:

  • the right kind of backflow prevention device is installed
  • the device is properly maintained (generally required to be inspected once a year).

Plumbing your rainwater tank to your home is the best way to maximise the use of your captured water, and devices like this ensure we can use rainwater in our homes and still protect our mains water supply. If you are interested in a quality rainwater tank for your home, contact the expert team a Team Poly today. Make an online enquiry or call us to talk directly.