Backflow Prevention - Testing, maintenance & installations

Backflow is when water flows in the opposite direction to where it’s meant to go. Instead of clean drinking water moving safely from the mains into your property, a sudden change in pressure can cause contaminated water to be drawn back into the public water supply.

This usually happens due to back-siphonage (a drop in mains pressure) or back-pressure (when downstream pressure becomes greater than supply pressure). Situations like water main breaks, firefighting activity, heavy water demand, pump systems, or elevated tanks can all create the conditions for backflow to occur.

When backflow happens, water from sources like irrigation systems, fire services, commercial equipment, industrial chemicals, bin wash areas, rainwater tanks or recycled water systems and even septic or grease traps can potentially enter the potable (drinking) water supply. This is obviously not ideal and can cause major health concerns not only for yourself but also to others.

That’s where backflow prevention valves come in. These devices are installed to stop contaminated water from flowing backwards into the mains. They act as a safety barrier between your property and the public water system.

Why It Matters

Backflow prevention isn’t just a technical requirement — it’s about protecting the publics health.

If a backflow device fails or isn’t installed where its required, contaminants such as fertilisers, chemicals, bacteria, or debris can enter the drinking water network. This can affect not just one property, but surrounding homes and businesses connected to the same supply.

Local councils require annual backflow testing and a form 9 submitted to ensure that these devices are working correctly and meeting Australian Standards. Failing to test or maintain a device can result in:

• Non-compliance notices

• Fines

• Water supply interruption

• Increased liability for property owners

Regular testing ensures your backflow valve is operating correctly, protecting both your property and the wider Noosa community.

To put it simply — backflow prevention is about keeping your drinking water clean.

Certified Annual backflow testing noosa

If your property has a registered backflow prevention device, local council require annual testing and certification by a licensed and endorsed backflow plumber.

Our backflow testing service includes:

• Full device inspection

• Pressure and performance testing

• Compliance certification (Form 9)

• Lodgement of Form 9 to the local council.

• Detailed reporting and documentation

• Repairs, servicing or replacement if needed

We make the process straightforward and easy to ensure you remain compliant and stress free.

Types of backflow prevention devices noosa

There are 6 main types of backflow prevention devices commonly used in Noosa:

1. Atmospheric Vacuum Breakers (AVB): These devices are a low hazard non-testable backflow device commonly found on all external taps. It is a single check valve spring loaded to a closed position with atmospheric vacuum breaker vent. They are generally attached to a hose tap to prevent back siphonage, for example in the event of cross connection when filling a swimming pool.

2. Single Check Valves (SCV): These devices are a low hazard testable device commonly used in fire services such as fire hydrants or fire sprinkler systems. They protect against contamination that is a nuisance but does not endanger health or cause injury.

3. Dual Check Valves (DuCV): These devices are a low hazard non-testable backflow devices commonly used in domestic settings. Using two independent, spring-loaded check valves in a series, they provide backup protection, ensuring that if one valve fails, the second still stops backflow.

4. Double Check Valve (DCV): These devices are a medium hazard testable backflow device generally used for irrigation supply or commercial settings. They also have two independent, spring-loaded check valves in a series, they provide backup protection, ensuring that if one valve fails, the second still stops backflow. These valves protect against contamination that has the potential to endanger health.

5. Reduced Pressure Zone Device (RPZ or RPZD): These devices are a high hazard testable backflow device that are commonly found in commercial settings where contamination has the potential to cause death. Utilising two check valves and an intermediate relief valve/vent port, it prevents back pressure and back siphonage and release excess water out of the relief valve/vent port maintaining an air gap when not in use.

6. Registered Air Gap (RAG): A registered air gap is an approved, physical and unobstructed vertical separation between a potable water outlet and the potential source of contamination (tank/vessel) used to prevent backflow. They are a high hazard backflow protection system that is commonly used for water carting trucks and industrial tanks. This system protects the mains supply from contamination that has the potential to cause death.

Who can replace, install or disconnect a backflow device noosa

Backflow devices must be installed, replaced, tested or disconnected by a licensed plumber with their backflow accreditation. In Queensland, this means a plumber who holds the appropriate plumbing licence and is endorsed to carry out backflow prevention work in accordance with Australian Standards and local water authority requirements.

Backflow prevention devices are part of the regulated drinking water system. Because they protect public health, they cannot legally be installed or altered by unlicensed contractors, handymen, irrigation technicians (unless appropriately licensed), or property owners.

When a backflow device is installed, replaced or removed, it may also require:

• Compliance with AS/NZS 3500 and AS/NZS 2845 plumbing standards

• Lodgement of certification paperwork

• Notification to the local water authority or local council

• Annual registration fees and testing (where applicable)

If a device fails its annual test, only a licensed backflow plumber can carry out the required repairs or replacement and provide the correct compliance documentation.

At Good Az Plumbing, we are fully licensed and qualified to install, replace, test and disconnect backflow prevention devices across Noosa and surrounding areas. We ensure all work is compliant, properly documented and completed to the required Australian Standards — so your property remains protected and fully compliant.