A study initiated by the National Water Commission analysed the cost-effectiveness of installing a rain water tank from the perspective of the home owner in different regions of Australia.  The study investigates how cost effective rain water tanks are as a substitute for mains water supply.

The report highlights that the yield and the cost of rain water tanks varies significantly based on individual household variables, including the size of the roof collection area, water tank size, number of occupants in the home and annual rainfalls. A water tank's yield is determined by both the volume and timing of run-off into the tank and the volume and timing of usage.

The water tank report is available as a PDF download from the Victorian Water Industry association website.