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Council adopted a Backflow Prevention and Cross Connection Control Policy (129kB PDF) in March 2014. This policy seeks to protect the water supply from contamination to safeguard public health. It formalises Council's existing guidelines relating to backflow prevention and cross connection control and aligns with new guidelines from the Water Directorate and regulation changes.


Backflow is any unwanted flow of potentially contaminated water back into Council's water supply system. This can occur when water flows backwards, or opposite to its normal and intended direction of flow.

Backflow is more likely to occur if the water pressure in a customer's property is higher than the pressure in the main. This can occur when:

  • There is a break in the main, resulting in a drop in pressure in the water main
  • The main is turned off and drained during construction or repairs
  • There is a significant draw on the water supply due to fire fighting activities or unauthorised high water use
  • If a pump is connected to the property water plumbing system

Backflow prevention devices have one of the following elements to stop water flowing backwards:

  • An air gap
  • A break tank
  • A valve
Most households in the Tweed will have a backflow prevention device built into their water meter.

Cross Connection

A cross connection is a direct or indirect physical connection between drinking water and non-potable water supplies or other contaminants such as chemicals, oil, bacteria, mud or debris.

Cross connection may result from:

  • Faulty plumbing within your premises

  • Hoses submerged in buckets, tanks or pools

Both backflow and cross connections can present a risk to public health. Cross connections contaminate the reticulated water supply system and is illegal.


Tweed Shire Council minimises the risk of contamination in its water supply system through backflow prevention and cross connection control. Council's policy outlines the responsibilities of Council, property owners and plumbers to ensure that the drinking water supply is protected.

Hazard Ratings

The risk of backflow and contamination varies depending on the situation. There are different backflow prevention devices which can be installed depending on the risk or hazard rating of the property concerned. Australian Standard AS 3500 defines three possible levels of hazard, namely:

  • Low hazard: Conditions, devices or practices which would not endanger health or cause injury if contamination occurs but constitute a nuisance. These are typically domestic properties (single dwellings, duplexes and units) where no commercial activity exists and no fire service is required.

  • Medium hazard: Conditions, devices or practices which could endanger health if contamination occurs. These are typically commercial/industrial properties with contamination risks such as chlorinators, fire hose reels, public swimming pools, marinas. These properties will typically have cross connection and backflow prevention installed during construction.

  • High Hazard: Conditions, devices or practices which have the potential to cause death if contamination occurs. This includes hospitals, abattoirs, irrigators using potentially harmful chemicals and dockside facilities.

For further information, see Backflow.

Fees and Charges

Council has set appropriate Fees and Charges in relation to backflow prevention. The fees are for:
  • Issuing permits
  • Inspecting backflow prevention device installations
  • Re-inspection fees (if required)
  • Annual registration and administration fees for backflow prevention devices
  • Other fees and charges as deemed appropriate.

Non Compliance

If the property owner fails to repair, maintain, replace or test a backflow prevention device as required by legislation, Council may use the provisions of the Local Government Act and Regulations to:
  • Have the defective work repaired
  • Apply penalties
  • Restrict or disconnect the water connection
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