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Our Commitment to Quality

Australian Standard 4766 - "Polyethylene Storage Tanks for Water and Chemicals" requires that 1 in every 10 water tanks produced pass a strict set of tests. This standard specifies requirements for the design and manufacture of polyethylene storage tanks that are rotationally moulded in one-piece seamless construction.

At Q Tank our commitment to quality demands that we test every tank, and we provide you with the testing report for every Q Tank you buy, so you know your rain water tank meets quality standards.

Each Q Tank must pass three tests before leaving the factory floor:

  • Ultrasonic Thickness Testing - Uses ultrasonic measuring equipment to measure the thickness of the water tank at various points in the roof, wall and base.
  • Impact Testing - Measures the plastic's impact strength and ensures the tank is not brittle and has been made correctly.
  • Visual Inspection - Our experienced staff perform a survey of the interior and exterior of the water tank.

Ultrasonic Thickness Testing

Ultrasonic Thickness Test

We use an ultrasonic measuring device to determine the thickness of our tanks to within 0.1mm accuracy. At Q Tank we use this device on 20 sections of the tank including areas of the lid, wall and base.

The Australian standard requires that no section is thinner that 4.5mm. At Q Tank, all our water tanks far exceed this standard.

We further test areas at a similar height on the tank, making sure they are a consistent width to ensure the tank's long-term durability.

You will receive the complete results of the thickness test with your test report, so you will know for sure the thickness in all areas of your tank.


Impact Testing


Measures the plastic's impact strength and ensures the tank is not brittle and has been made correctly

  1. When the inlet strainer is cut from the tank, 2 samples of the tank are removed ready for impact testing. (one is supplied with the tank, the other is kept at Q Tank for warranty period of the tank).
  2. The sample is allowed to cool slowly at room temperature for 24 hours, then cooled to -40° Celsius for 6 hours to stress the polymer chains to their limits.
  3. A 9kg dart is dropped onto sample to test its strength (see adjacent image). If the sample cracks or is pierced then the tank fails the test and will not be sold.
Impact Test

Visual Inspection


The interior and exterior of the tank is visually by our experienced staff to check for defects. When rotary moulded polyethylene water tanks are over-cooked they degrade from the inside out. It takes the trained, experienced eye of our skilled staff to spot these possible defects before any tank reaches the public.