Alternative Water Supply

An alternative water supply is a water supply fed from a non mains water source. In industry, this typically includes water sources such as roofwater, filtered stormwater and recycled process or wastewater.

Drinking water has historically been used to supply nearly all water demands in urban Australia regardless of whether drinking grade water was required. This was possible when community concern for water security was low and water utilities sought to maximise water sold.

As population growth and changing rainfall patterns shift the traditional supply and demand balance, and ageing infrastructure coupled with more dense development and increasing construction costs threaten the ability of water utilities to cost effectively service all demands, alternative water supply has become a key strategy for water utilities to manage demand growth.

Many industries remain reliant on the drinking water supply system as a legacy of past water supply practices. Industrial precincts do however lend themselves well to alternative water supply:
Large non-potable water uses which can deliver substantial drinking water savings;

Concentrated water usage points in often open-plan facilities that are accessible for new plumbing; and

Extensive roof and pavement areas that provide a high conversion of rainfall to runoff and an abundant source of supply.
Households also typically use drinking water for all demands however it is generally not feasible to retrofit existing households with an alternative water supply for internal use. Rainwater tanks are becoming common for outdoor and indoor use in new developments and some urban areas offer a non-potable mains supply.

The evolution of alternative water supply in Australian industry is summarised in the timeline below.

Alternative Water Supply Timeline

Roofwater Harvesting

Roofwater harvesting provides a supply of high quality water suitable for use in non-potable applications such as toilet flushing and landscape irrigation with minimal treatment. More


Stormwater Harvesting

Stormwater harvesting delivers larger volumes of poorer quality water suitable for high water using applications such as cooling towers or industrial processing. More