"I would not drink it for sure.
Flinders University environmental health researcher Kirstin Ross, who recently conducted a review of tank water around Adelaide, said that although there was no evidence of increased gastrointestinal illness as a result of using rainwater tanks for drinking water, the microbes are present in the water.
But with many Australians without access to town water and reliant on rainwater, what precautions should we take to make sure our tank water is safe to drink?
Under lab conditions filtration systems are able to remove E. coli, Dr Ross said, but filters in homes often became a breeding ground for the bacteria.
"Filtering might be enough if they use a well-maintained filter.
Filtering can also remove some — but not all — of the dangerous metals that have been found in many Australian water tanks.
"Filtration will remove some of these metals, but not all – we did a study on water that we artificially contaminated with bushfire ash, to see what recommendations should be made post-bushfire to landholders, and found that filters were good at removing zinc and copper but not chromium and arsenic," Dr Ross said.
If mosquitoes can access the water in the tank it can become a breeding ground for the disease-spreading insects, said Dr Moglia, who was part of a research project that inspected 450 tanks across Melbourne.
And check your mesh is in good nick every three months; a recent CSIRO study found more than 10 per cent of water tanks inspected had mesh that was in poor enough repair to let pests and vermin into the tank.
And there’s a bigger environmental benefit of more homes having rainwater tanks, especially in urban areas, according to Dr Moglia: reducing runoff into waterways.