Towards sustainable water strategies in the Perth Region of Western Australia: inclusion of decentralised options

This study presents the impact of including decentralised rainwater harvesting, water efficient appliances and wastewater reuse strategies in analysis of the operation of regional water supply systems. These strategies provide significant reduction in regional water demand, improvement in regional water security, decreases in greenhouse gas emissions and economic benefits. A compelling case has been made for the inclusion of decentralised water management options in analysis of regional water systems. This is a contrast to the normal practice of uncritical dismissal of decentralised options prior to detailed systems analysis. The results indicate that adoption of 3 kL rainwater tanks for hot water and laundry uses, water efficient appliances and estate scale wastewater reuse for outdoor and toilet uses for all new housing, and 3 kL tanks for laundry, toilet and outdoor uses with water efficient appliances at a rate of 1% per annum to existing houses may be optimum