Sydney's hunt for water goes underground

Sydney's water crisis deepened today and so did it's search for water.

The NSW government is now looking underground, inside mines in its hunt for new water sources.

Environment Minister Bob Debus revealed to National Nine News today that the amount of water stored in operating and abandoned mines is worth further investigation.

"It's possible there could be up to fifty gigalitres, that is to say fifty billion litres of water a year available out of mines," he said.

That's equivalent to more than a month's supply every year for Sydney. The government is now working out the cost of removing and treating the water.

Today Sydney's water supply fell to its lowest on record — 37.5 per cent.

The crisis isn't likley to ease in the short term. Water usage increases in Sydney over summer and the long range weather forecast is that significant rain isn’t expected in the catchment area.

"We have no guidance suggesting sustained wet periods in the next three months so it doesn't look good," said the Weather Bureau's Clinton Rakich.