Rainwater tanks

Benefits of a rainwater tank


Install a rainwater tank and save both water and money. A rainwater tank provides you with the following benefits:

  • Free water; saving money on water rates.
  • Soft water that lathers easily, saving on soap and detergent.
  • Extra water available to:
    • Water gardens and lawns
    • Wash cars
    • Clean building surfaces
    • Wash patios and driveways
    • Top up swimming pools.

Read more: Benefits of a rainwater tank

Healthy rainwater tanks & maintenance


High quality tank water is dependant on the owner’s maintenance of a healthy tank.  Proper maintenance involves the cleaning of gutters and downpipes and checking for mosquito and vermin control. Tank installation could include a “first flush” system to divert the initial scour of dirty rainwater away from the tank.

If water is only to be used for non-drinking purposes, such as in the washing machine or toilet, then it is unlikely that any treatment will be required, although filtering does limit some contamination. If water is to be provided for other household uses that involve contact with humans, such as drinking, showering or cooking, additional treatment should be considered; potentially ultra-violet disinfection.

Read more: Healthy rainwater tanks & maintenance

Tank water safeguards


When installing a rainwater tank attaching several simple devices may assist in keeping the tank water quality in reasonable condition.

Gutter guards prevent leaf litter entering the tank

If leaf litter enters the gutter, this debris may accumulate and block the rainhead or inlet screen causing uncontrolled overflow and reduce the amount of rainwater collected.

Read more: Tank water safeguards

When a rainwater tank requires approval

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 from Council. However, you will need to follow guidelines on related issues such as where to locate the tank and how to discharge water overflow.

What to consider when retrofitting a tank

When retrofitting to an older existing home there are several things you need to consider such as what size tank and how much water will be collected.

What size tank should I buy?

When planning to install a rainwater tank, you should determine:

  • The intended use of rainwater
  • Volume of water needed for these uses
  • Roof area supplying the tank

Read more: What to consider when retrofitting a tank

Where can I discharge the overflow from the tank?

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 mor the TRC Planning Scheme.

Related documents

No related documents.

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