Backflow Prevention

Shoalhaven Water has a responsibility to provide safe drinking water to our community from the point of treatment to the point of use.  Commercial or industrial property owners are responsible to ensure that they do not affect the mains supply with any contaminated water from their property. 

Backflow Prevention Device

Backflow & Cross Connection Explained

Backflow is the unwanted flow of potentially contaminated water into the potable (drinking) water supply. Our water distribution system is designed to ensure that water flows to a property under pressure, if this pressure is not maintained there is a chance that water could transfer from a property back into the main water supply.

Backflow can occur in two ways:

  • Back Siphonage is a condition that can occur when a negative pressure occurs in the main and contaminated liquids enter the potable water supply by siphonage.
  • Backpressure is a condition where the pressure downstream becomes greater than the pressure upstream of the cross connection thus allowing water or other contaminated liquids to enter the potable supply.

What is a Cross Connection?

Cross connections are actual or potential physical connections between potable and non-potable water. There is a risk to public health if there is a cross connection between a water supply and a contaminated source.

The most common situation involving cross connection is with unmetered fire services and internal plumbing of water tanks. Other examples of where potential cross connections are likely to occur are – market gardens, dairy farms, commercial kitchens, clubs & hotels, dental surgeries, funeral parlours, hospitals, and mechanical workshops.

Cross connections without proper backflow prevention can cause health issues for water supply customers. By protecting our water supplies from contamination, we can better protect our community from harmful hazards.

What is a Backflow Prevention Device?

A backflow prevention device is a device that prevents the reverse flow of water from a potentially polluted source into a potable water supply system. They are either testable or non-testable. All testable devices must be registered with Shoalhaven Water and tested annually to ensure correct operating condition. 

Backflow devices are installed downstream of the boundary meter and depending on the business activity occurring on the premises, there are different devices designed to minimise the risk of a potential contamination. 

Under AS/NZS 3500.1 the three hazard ratings are as follows:

  • High Hazard – any condition, device or practice in which connection with the water supply system has the potential to cause death
  • Medium Hazard – any condition, device or practice in which connection with the water supply system could endanger health
  • Low Hazard – any condition, device or practice in which connection with the water supply system could constitute a nuisance but not endanger health or cause injury

What is a Backflow Survey?

Through the Development Application process we can identify if your proposed business activity may pose a potential hazard to our water supply. 

If we determine there may be a potential hazard from your proposed activity we will ask you to obtain a Backflow Survey from a plumber or hydraulic consultant who will assess the property and recommend backflow prevention solutions. Surveys can be submitted in the form of a signed letter or statement which includes the following information:

  • Hydraulic consultant or plumber’s name, address and qualifications (eg license no)
  • Address of property being surveyed
  • Hazard rating of property
  • Type and location of proposed device/s

Requirements to Protect our Water Supply

Working together we can protect public health and the environment. If your business activity has been determined to be a risk to our water supply and a backflow prevention device has been proposed, you will be required to engage an accredited backflow plumber to install a backflow prevention device, in the first instance at the property boundary adjacent to the water meter. Depending on the onsite activities, further devices may be required to protect individual fixtures or zones. 

How do I register a new device?

A new testable backflow prevention device must be tested immediately after installation by an accredited backflow prevention plumber. After testing, the plumber will forward a Test & Maintenance Report to us with the property details, site contact and device details to initiate the registration of the device.

Once the device has passed inspection for correct installation in line with the Australian Standard AS3500.1, device details will be registered in our system for ongoing testing and maintenance.

Registration Details

In order to protect our potable water supply from potential unwanted contaminants, AS/NZS 2845.3 states once a device is installed it will require annual testing to ensure continued effective operation of the device. 

Annual Registration – Shoalhaven Water will issue an annual reminder that the device is due for testing along with an annual registration fee. You will be required to engage an Accredited Backflow Plumber to test all relevant devices on the property. The plumber will submit a report to Council for each device tested

Follow this link to view our list of local Accredited Backflow Plumbers.

Overdue Testing Penalty - Late submission of test reports will incur a penalty. Should penalty fees not cause the testing of device to be undertaken, Shoalhaven Water will arrange the required test and pass charges onto the owner. Legal action or disconnection of services may also occur noting the seriousness of water supply protection.

Any associated fees will be charged to the property owner, should the business or property change ownership you must notify us in writing to avoid being sent Annual Reminders or Overdue Fees. 

Changes to Business Activity

If you believe that the backflow prevention device is no longer required on your property due to a change in business activity, a new backflow survey will be required to be undertaken and submitted to Council.  If approved, you will be notified that the device may be removed.

Information for Accredited Backflow Plumbers

Shoalhaven Water keeps a list of local accredited backflow plumbers. If you would like to join our list, you must provide a copy of your TAFE certificate and contact details.

Backflow Test & Maintenance Report Books are available for sale from Council.

If you are an out of area plumber, TAFE certification must be provided along with the test report. We do not have a system of on-line test reports available, but we will accept Sydney Water or Hunter Water test report forms, or in-house forms that comply with AS/NZS2845.3.

Need more help?

For further information regarding Backflow Prevention contact us on 02 4429 3125.

Appointments are necessary if you come into the office to discuss.