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Water backflow prevention

 135 Byng St, Orange
 02 6393 8000
 [email protected]

Chemicals used by businesses could end up getting back into the main water system, which is why it is compulsory for every business  to have a backflow prevention device.

All properties with a water inlet pipe bigger than 20 mm (usually businesses or unit blocks), must have a backflow prevention device, and it’s usually installed at the same time as the water meter.

‘Backflow’ is the unintended reversal of the flow of water or other liquids from a property back into the city’s water main.

This can occur if there is a sudden reduction in pressure in the city’s system of water pipes (reticulation system).

This could occur if a pipeline breaks or can be caused by:

  • Back siphonage – where the pressure in Council’s water supply system becomes less than the atmospheric pressure within a connected property, causing water to flow backward into the City’s supply.
  • Back pressure – when the consumer’s water pressure is greater than the pressure in City’s supply.
  • Cross-Connection – connection of a potable water supply to a line that is non-potable, eg city water supply to a non-potable bore.

In industrial and commercial premises, water may have been contaminated with chemicals used on the property, so backflow can represent a serious health risk to Council’s other customers.

Backflow prevention devices prevent this potential problem happening.

The question of which device needs to be installed on which property is determined mainly by the activity carried out on site and the potential risks of this activity.

Orange City Council’s water policy requires the property owner to ensure that a backflow device is installed and is working.

To show this is happening, property owners must be able to produce documents showing test results.

The Water Supply Policy can be downloaded here.

Frequently Asked Questions

Why is Backflow ‘prevention’ a concern for Council?

It is a concern for Council because this water may be contaminated with chemicals.

If the contaminated water enters the city’s system of water pipes (water reticulation system) it could be used by another customer causing health issues to the customer and liability issues for Council.

Why do I need to install a backflow prevention device?

All properties with a water connection of more than 20mm must have a backflow prevention device in accord with the Plumbing Code of Australia, some of which are testable devices.

Council will assign a default level of hazard based on an assessment of the primary activities being undertaken on site.

A licensed plumber with backflow prevention accreditation will assist in determining the type of device required.

If your property has more than one meter you will need to install a device on each of the water meters.

How do I know which is the best backflow prevention device for me?

The policy is a risk based policy. The activities undertaken on the property determines the hazard rating, which in turn determines the backflow prevention device needed.

Council will use a default hazard assessment unless the property owner supplies specific information that would lead to assignment of a different hazard.

Hazard Rating

(a) High hazard – Any condition, device or practice that, in connection with the drinking water supply system, has the potential to cause death. Testable Device.

(b) Medium hazard – Any condition, device or practice that, in connection with the drinking water supply system, has the potential to endanger health. Testable Device.

(c) Low hazard – Any condition, device or practice that, in connection with the drinking water supply system, constitutes a nuisance but does not endanger health or cause injury. Non-Testable device.

You need to inform Council of any changes to the business activity undertaken on the property, so that the hazard may be reconsidered. The type of device is dependent upon the device’s hazard rating. Some examples are listed below.

Device Hazard Rating

Reduce Pressure Zone Device (RPZ) High
Registered break tank/air gap High
Testable double check valve Medium
Testable double check detector assembly Medium
Non-Testable devicesLow

Zone Backflow Prevention Devices

Some businesses have different areas, or zones, within their premises which have different hazard levels.

For this reason, businesses can install zone backflow prevention devices throughout the property as well as the ‘site containment’ backflow prevention device.

The zone backflow prevention devices are installed to protect drinking water (potable) on the property from potentially contaminated water such as rainwater or grey water, integrally connected to the potable system.

I have a testable backflow device. How does the Policy affect me?

The Plumbing Code of Australia requires property owners to test these devices every 12 months. A licensed plumber, who has completed additional training in backflow prevention, must undertake the test and forward the results to Council.

Who can I get to undertake the regular 12 monthly test of my backflow prevention device?

A licensed plumber who has completed special NSW Government backflow prevention training.

What if the testing reveals maintenance is required or the device needs replacing?

Minor maintenance such as renewal of seals or springs could normally be carried out by the plumber when undertaking the testing.  Under Council’s policy, the replacement of the device at the end of its life is the responsibility of the property owner.

What happens if a property owner does not undertake backflow device testing when required?

If a property owner doesn’t have their device tested, under Council’s policy, there are a number of enforcement options, ranging from council staff doing the work and charging the customer, to disconnecting the property from the water supply.

Why do I have to tell Council of changes in my business activity?

If the business activity changes within a premises, the hazard rating assigned may be affected. An accredited backflow licensed plumber should be engaged by the property owner to re-assess the hazard rating.

Disputing a Hazard Rating – There may be instances where the property owners disagree with the default hazard rating assigned to their premises. In this case, the property owner should engage an accredited backflow licensed plumber to re-assess the hazard rating and submit the proposal in writing to Council for approval.

Change of Hazard Rating – All requests to Council to review backflow prevention hazard ratings should be made by an approved plumber on behalf of their customer.

Property owners can submit to Council an Application to Review Backflow Prevention Hazard Rating, along with any supporting information that may assist the claim.