A continental scale evaluation of rainwater harvesting in Australia

In this study, we have examined the viability of rainwater harvesting system in whole Australia in terms of water savings, reliability and financial viability. Three different cases of water use have been considered: (i) toilet flushing and laundry; (ii) irrigation; and (iii) combination of toilet flushing, laundry and irrigation (combined). The analysis is performed using data from 601 Australian rainfall stations. The results show that the reliability of a rainwater harvesting system is considerably high (80-100%) for 'toilet flushing and laundry' use. For 'combined' use, the reliability drops below 50% for most of the continent. We have presented the detail results of spatial distribution of reliability and water savings for a tank size of 7.5 kL. It is found that the benefit cost ratio for rainwater harvesting system over one can be achieved under certain conditions. The findings of this study will be useful in sustainable water resource management in Australia using rainwater harvesting system.