Recent rain has simply highlighted the need for a widespread roll out of rainwater tanks, an environment group said this week, in the wake of a report that showed that installing rainwater tanks could be cheaper than desalination.
Figures show that in 48 hours this week, over 99mm of rainfall fell at Observatory Hill in Sydney. Over the same period, just 8mm was recorded at Camden, close to Sydney's main water catchments.
The report - prepared by economists Marsden Jacobs Associates for the Australian Conservation Foundation, Environment Victoria and the Nature Conservation Council of NSW - found the widespread installation of rainwater tanks in Australian capital cities would mean big savings in water, energy and money.
Cate Faehrmann, Executive Director of the Nature Conservation Council of NSW said that "household rainwater tanks connected to the laundry and toilets provide huge savings and could defer the need for a desalination plant until 2026".
"Rebates alone are not enough to have the more than one million suitable households in Sydney have a rainwater tank installed", Ms Faehrmann said.
"The NSW Government could organise a mass rollout of tanks that would provide water security for Sydney and other coastal areas.
"While governments are busy pushing new dams at Tillegra in the Hunter or on the Clarence River, they are overlooking the greenhouse friendly option of rainwater tanks", she added.
The report claims that not only are rainwater tanks five times more energy efficient than desalination plants, they are twice as energy efficient as Queensland's proposed Traveston dam, per megalitre of water produced.
What is more, because of their placement, dams often do not capture the same rainfall levels as the coastal fringe, leading to a "green drought", where rain falls in the cities and runs out to sea, but shortages remain in place because dam levels do not rise.
"If governments deployed rainwater tanks to 5 per cent of households each year in Sydney and South-East Queensland, dams and desalination plants planned for 2010 could be delayed past 2026 (Sydney) and 2019 (SEQ)."
It has been found that most Australian houses would be ideal for installing rainwater tanks, especially with the wide range of shapes and sizes available now. In Sydney 65 per cent (or 1.1 million houses), in South East Queensland 73 per cent (or 900,000 houses) and in Melbourne 72 per cent of existing houses have the potential to benefit from a rainwater tank.
In the report, ACF's urban water campaigner Kate Noble said while 38 per cent of households in Adelaide have rainwater tanks, fewer than 6 per cent of the houses in Melbourne, Sydney, South-East Queensland and Perth do.
"Rainwater tanks collect and store water far more efficiently than dams, especially in times of drought. As the climate changes we should be installing tanks to take advantage of the rain that does fall on our rooftops", Ms Noble said.
"If governments systematically installed rainwater tanks in Australia's major cities, we would secure as much water as the planned Kurnell desalination plant in Sydney, the Tugan desalination plant on the Gold Coast and the stage one of the unpopular Traveston Dam proposed for Queensland's Mary River," she added.
