Monash University researchers, in conjunction with Water Quality Research Australia (previously the Cooperative Research Centre for Water Quality and Treatment), studying the health of families with the highest use of rainwater tanks in Australia, found it to be safe for drinking.

The first study of its kind, it involved three hundred volunteer households in Adelaide provided with half real and half sham filters for treating their rainwater, without being told which filter they had received. They were asked to record their health over a 12-month period, with a comparison of health outcomes of the two groups made after that time period.

Results showed similar gastroenteritis rates between both groups, with those no measurable increase in illness displayed when compared in either group.

The study confirms low risk of illness from drinking rainwater, proving the safety of rainwater for household purposes and implies it can be used for activities like showering/bathing, where it is possible to inadvertently or accidentally ingest small quantities of water.