Rainwater Tank Use

The South Australian Murray-Darling Basin Natural Resources Management Board (SA MDB NRM Board) aims to support the community to reduce reliance on the water resources of the River Murray and Eastern Mount Lofty Ranges. The installation of appropriately sized rainwater tanks that are plumbed for maximum internal use and/or garden use, are ways in which demand for mains water and other raw water supplies can be significantly reduced.

The installation of water efficient devices and appliances such as AAA rated shower heads, 3/6L dual flush toilets and front loading washing machines provide further water savings.

Information Sheets

The SA MDB NRM Board Rainwater Tank Use Fact Sheet # LG01 provides an overview of the information to be considered when planning, constructing and maintaining your rainwater tank collection system

Tips for Saving Water in your Home and Garden (130kb)

Rainwater Tank Use Facts Sheet LG01 (518kb)

Building Code

From the 1 July 2006 new homes and household extensions of greater than 50m2 are required to install a rainwater tank plumbed for internal use. This requirement generally applies to new Class 1 buildings, which are defined by the Building Code of Australia BCA2005 - Volume 2.

This announcement was made by the Premier on 5^th March 2004. The announcement was made as part of Government's response to recommendations made by the State's first Thinker in Residence, Herbert Giradet. Herbert Giradet is a highly qualified urban ecologist and an expert in making cities and communities live within their means from an environmental perspective.

For full details of the legal requirements refer to the Planning SA Advisory Notice – Technical Building Code of Australia: Mandatory plumbed rainwater tanks for Class 1 buildings.

Rainwater tank size selection

Many households within the SA Murray-Darling Basin currently capture rainfall runoff from the roof in a rainwater tank. However most households could gain greater value from their rainwater tank if they connected the rainwater to all major household use, eg toilet (WC), laundry, hot water service (HWS). Essentially the more rainwater a household uses, the more storage is available in their tank to capture additional rainfall, and hence the household can maximise the yield from the rainwater tank annually.

The amount of rainwater a household can capture, store and use annually is dependent on:

• the annual rainfall;
• the roof area connected to the tank;
• how much rainwater you use and when you use it; and
• the capacity of the tank you choose to connect.

The following rainwater use options have been modelled based upon the rainfall patterns for the major townships within the SA Murray-Darling Basin, to help households select the appropriate sized rainwater tank given the intended use of the water and the roof area connected to the tank.

Option 1 – “High internal use” : 11L single flush toilet, 100% laundry ( front load WM) & HWS.

Option 2 – “Medium internal use 1”: (6/3L) Dual flush toilet, AAA-rated shower head, 100% laundry (top load WM) & HWS.

Option 3 - "Medium internal use 2”: (6/3L) Dual flush toilet, AAA-rated shower head, 100% laundry (front load WM) & HWS.

Option 4 – “Low grade uses”: (6/3L) Dual flush toilet and 100% laundry (front load WM) only.