Landcare Research - Manaaki Whenua

Landcare-Research -Manaaki Whenua

Rain tanks

People have relied on rainwater for household, landscape and agricultural water uses for centuries. As communities have become larger and more centralised, community water treatment and distribution systems have gradually replaced the collection of rainwater as our primary water supply. As we have begun to understand the need for sustainable use of water worldwide there has been a renewed interest in collecting rainwater.

Rainwater tanks for both detention and domestic use are being used in several properties in Auckland. At one neighbourhood development potable water supply is via mains connection; however, rainwater is collected (13,500 L tanks) and re-used for toilets, laundry and external uses on 8 of the 13 houses.

Using rainwater:

  • Reduces demand for mains water supply and you save on your water rates
  • Reduces flooding by providing temporary storage for rainwater
  • Reduces wet weather sewage overflows
  • Reduces pollution of our beaches and waterways

Various regulations govern the installation and use of rain tanks and these vary with each local authority. It is advisable to contact your local authority if you are considering installing a rain tank to determine if a building or resource consent is required. Some councils offer incentives or rebates for installation of rain tanks.


  • Mithraratne N 2010. Rain tanks: are they really green? LG New Zeland local government 46(12): 14-15.
  • Mithraratne N, Vale R 2007. Conventional and alternative water supply systems: a life study. International journal of environmental and sustainable development 6(2): 136-146.
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