Air Gap Testing

Aussie BACKFLOW is Melbourne’s most trusted name when it comes to expert air gap testing and achieving backflow compliance.

What is a Registered Air Gap

Is an approved method of achieving backflow compliance and is the unobstructed vertical distance through free atmosphere between the lowest opening of a water supply pipe and the highest possible water level in the receiving tank or vessel.

Air Gap Testing

Air Gap Testing And Break Tanks

Isolating water sources from possible cross-contamination is often required in a variety of applications. Aussie BACKFLOW has mastered the protection of potable water supply via Air Gap Break Tank Systems.

AG and BT’s are non-mechanical backflow prevention devices that are very effective where either backsiphonage or backpressure conditions may exist. Air Gap and Break Tanks are considered suitable for Low Hazard installations only.

These would include: 

  • Hair salons basins or troughs
  • Irrigation systems on residential properties
  • Private bores of known water quality on residential properties
  • Rainwater tanks on residential properties

An Air Gap could cause a corresponding loss of pressure to downstream outlets. However, they are an extremely effective backflow preventer when used to prevent back siphonage and back pressure conditions. Consequently, annual Air Gap Testing plays a vital role in the prevention of clean water supplies.

Air Gap Testing

A Rain Water Tank with an Air Gap to prevent backflow

4 Things To Consider When Using An Air Gap To Achieve Backflow Compliance


The Air Gap may be easily defeated in the event the “2D” requirement was purposely or inadvertently compromised. Excessive splashing may be encountered if higher than anticipated pressures or flows occur. The splash may pose a nuisance or hazard, e.g. by creating undue noise or splashing water onto a nearby areas. In these situations, the solution often used is to reduce the “2D” height by thrusting the supply pipe into the receiving funnel or tank, or by attaching a hose. By so doing, the Air Gap is defective and the water service is unprotected from the hazard. This situation does not comply with the Plumbing Code of Australia.

Air Gap Testing


In a continuous piping system, each Air Gap requires the added expense of a Break Tank and secondary pumping system, assuming gravity will not provide adequate pressure.


At an Air Gap , water is exposed to the surrounding air with its inherent bacteria, dust particles and other airborne contaminants. In addition, the aspiration effect of the flowing water can drag down surrounding contaminants into the Break Tank.


Free chlorine can come out of treated water because of the Air Gap and the resulting splash and churning effect as the water enters the Break Tank. This reduces the ability of the water to withstand bacteria contamination during long-term storage.

Why Choose Aussie BACKFLOW

Aussie BACKFLOW is Melbourne’s most experienced and professional backflow testing service. If your business or home in Melbourne requires backflow prevention then we are able to help you meet all your backflow prevention obligations. With over 10 years experience we can test, repair and install any backflow prevention system for commercial and domestic customers. To speak to an expert today call 0488 410 033 and we’ll be happy to discuss your needs or arrangement a free quote and inspection.

100% Compliance with your local water utility.

Fixed Price Testing Solutions.

Free annual reminders and inspections.

All our work is fully guaranteed.

We service all the major water suppliers and are Accredited Backflow Prevention Testers.

Call Us Today

We are here for all of your backflow requirements!