The City of Sydney is seeking tenders to develop a Decentralised Water Master Plan aimed at producing more than 10% of the City’s water supply from local sources.

Currently, the inner city imports drinking-standard water from Warragamba Dam, but only 20% of this is used for drinking, cooking and washing. 80% is used for purposes like toilet flushing (19%) and air conditioning cooling towers (15%) which do not need drinking-standard water.

The tender, which closes on September 7, will explore different business models to implement the master plan, including a private sector water services company or a public/private joint venture.

The infrastructure required to capture and treat the recycled water would piggyback the council’s plans to install trigeneration power plants in buildings in the city. Trigeneration power plants use the waste heat from electricity to heat and cool buildings.The recycled water would be treated by waste heat from the trigeneration system and would be cheaper than importing treated water from Warragamba Dam.