When a rainwater tank requires approval and appropriate overflow

A building approval is required for rainwater tanks where one or more of the following criteria applies:

  • The base diameter of the rainwater tank exceeds 3.56 metres; or
  • The overall height exceeds 2.4 metres from natural ground level; or
  • The base is greater than 5 metres in length; or
  • A supporting structure (i.e. tank stand) is required and the overall height is over 2.4 metres; and
  • Where the tank is mandatory under the Queensland Development Code (i.e. new building construction); and
  • An underground tank with an excavation of over 1 metre; and
  • Building approval may be required if the rainwater tank is located within 1.5 metres of another structure (i.e. retaining wall).

In other circumstances you do not require building approval. However, you will need to follow guidelines on related issues such as where to locate the tank and how to discharge water overflow.

Tank overflow

Stormwater from roofed areas and overflow from any rainwater tanks is to be collected and discharged using one or more of the following techniques.

  • To the system of inter-allotment drainage.
  • Via an underground pipe to the street channel. All stormwater drainage pipework within the road reserve must be concrete, steel, FRC or Class 12 UPVC.
  • Where the grade does not permit the stormwater to be piped to the street channel, it is to be discharged via an underground pipe with a bubbler outlet at least 3 metres from the downstream side of all building foundations and no closer than 3 metres to any property boundary in a manner so as to cause minimum inconvenience to adjoining property owners.
  • Absorption trenches are installed a minimum of 3 metres from any downstream boundary. This is to comply with AS/NZ3500.3.2 Parts 6.4 and 6.5.

This is in accordance with the Queensland Development Code. Read more in the our Planning Scheme.

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