Backflow occurs when water flows backwards into the public water network. An unwanted reverse flow can cause contaminants – such as harmful bacteria or chemicals – to enter the water supply. This can seriously affect the quality and safety of drinking water.

What causes backflow?

We ensure that water flows to your property under the correct pressure, but if this pressure changes there is a chance that water could be drawn back into our network.

The two main causes of backflow are:

1. A sudden drop in pipe pressure, which siphons water back into the network.

2. If the water supply is directly connected to equipment, such as a boiler or a private bore which is at a higher pressure, water is forced back into the network.

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What is a backflow prevention device?

A backflow prevention device protects the water supply from potential contamination.

The type used (e.g. reduced pressure zone, double-check valve) depends on the degree of risk.

The device is usually attached to the water meter on the customer side of the point of supply.

Who installs and tests backflow devices?
Which water connections require a backflow device?
What information is required when I apply for a connection?
Is my property a backflow risk?
Where are the devices installed?
More information