Examining Biophysical and Socio-Demographic Factors across Mandated Tank Users in Urban Australia: A Linking Step towards Achieving Best Practices

This study examines biophysical and socio-demographic factors potentially affecting water use patterns of households with mandatory rainwater tanks in South East Queensland (SEQ). The Queensland Development Code (QDC) MP 4.2 promotes the use of rainwater tanks at the domestic level to reduce direct reliance on mains water supply. A sample of 1,134 mandated rainwater tank households were surveyed across SEQ. Results indicated that the majority of participants (78%) had tanks of 5 kL in capacity or larger, with 35% of householders having at least half of roof catchment area connected to their tanks. Also, the majority of participants utilised their rainwater for toilet flushing (97%), clothes washing (94%) and garden irrigation (77%). These biophysical findings indicate a high level of compliance with the QDC MP 4.2 code. Social factors affecting potential yields from mandated rainwater tanks were also examined, to complement the biophysical data obtained. It was found that the majority of tank users were happy to use rainwater as an alternative water supply option for non-potable uses. However, most participants reported being unaware of past or present water restrictions to their water supply, highlighting important social implications for total mains water savings. In conclusion, this study presents important biophysical and social descriptions about mandated water users in urban SEQ, as well as providing a foundation for future modelling of actual yields from mandated rainwater tanks to facilitate improved assessment of mains water savings due to the implementation of mandated rainwater tanks.