But despite his warning, Professor Collignon says he supports the use of recycled water for industry or to water lawns.
"Singapore is put up as an example of people who use recycled water and drink [it], but that’s actually not true," he told the ABC’s AM program.
"They have two different systems for their water where the water that’s recycled from sewage is almost entirely used in industry."
He says recycled water should be used first for industry or to water lawns and only used to top up drinking supplies when no other water saving measures are available.
Professor Collignon was speaking before a Senate inquiry into south-east Queensland’s water crisis.
The use of recycled water is being considered by several states as dam levels reach critical lows.
Last year a referendum in the south-east Queensland town of Toowoomba rejected a plan to use recycled water in the town’s drinking-water supply.
© 2007 Australian Broadcasting Corporation
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