Congratulations on your decision to harvest rainwater. This guideline is provided by the Rainwater Harvesting Association (RHA) and Urban Water Cycle Solutions (UWCS) for above-ground rainwater harvesting systems connected to residential dwellings in urban areas.
The specification is for a dual water supply, using mains water and rainwater sourced from roof catchments. The dual water supply system sources rainwater first, when stored rainwater is available, for outdoor, toilet, laundry and hot water supply. When stored rainwater is not available, all household water demands are supplied with mains water. The household is encouraged to choose the highest level of water efficiency.
Correctly installed rainwater harvesting systems develop a natural treatment train that addresses many of the potential contamination issues that may be associated with a roof catchment. This is an important reason why rainwater harvesting is so widely used in Australia and rainwater users remain healthy. Australian health data indicates drinking untreated rainwater provides health outcomes similar to mains water. One in four households use rainwater harvesting in Australia, and the householder is responsible for the quality of the water in their house for all water uses.
The RHA, through Professor Peter J Coombes from UWCS and other independent scientists, has extensively monitored the inputs and outputs of residential rainwater harvesting systems, and used that data to inform this design specification. This evidence provides a perspective that is independent of the traditional water industry and the centralised distribution paradigm.
Additional rainwater harvesting information is available at urbanwatercyclesolutions.com.
