Australian governments should immediately begin integrating recycled sewage into their drinking water plans, despite the severe water shortages of recent years easing in most capital cities.
Speaking today at Australia's biggest annual water summit, one of the nation's top water officials will tell governments not to ''wait until the next crisis'' to start their planning.
Believing that recycled sewage will play a big role in future drinking water supplies, Australian Water Association chief executive Tom Mollenkopf will tell today's summit that governments are jeopardising Australia's future water supplies by refusing to consider ''indirect potable re-use''.
''Governments should be examining other alternatives now and that includes adding purified water to our drinking water supply," he said.
''Desalination and other initiatives have bought our cities some time, but these projects will be pushed to the limit as Australia's population grows from 21 million to an estimated 35 million by 2050.
''In 20 to 30 years many cities will be looking for the next solution to increasing water needs ... let's not wait until the next crisis before any further action is taken.''
What loomed as a national water crisis has eased over the past year, as improved rain in north-eastern Australia and projects like desalination have reduced the threat of capital cities running out of water.
Melbourne's dams remain at only 34 per cent of capacity, which is higher than at the same time last year, and will be boosted by 75 days worth of water through the north-south pipe this year.
The Victorian government was criticised by many, including the auditor-general, for responding to water shortages with an infrastructure plan that ''lacked rigour'' because of its hasty development.
Mr Mollenkopf said starting work now on the next water plan would allow the most affordable, appropriate and environmentally friendly options to be chosen.
''One of the things about [adding recycled water to drinking supplies] is it's emotional and there's a lot of things that need to be considered to ensure public health,'' he said. ''You don't want to race it, so let's start the discussion now so nobody feels as though they are being blindsided.''
Two previous attempts to add recycled sewage to drinking supplies in Australia have failed, and Mr Mollenkopf said both campaigns fell victim to politicisation and a lack of calm public debate.
He said that in many cases recycling sewage would require less energy and capital costs than alternatives like desalination.
The Victorian government is opposed to the drinking of recycled sewage, despite a study in 2006 finding it could be done in Melbourne at less financial and environmental cost than seawater desalination.
Despite the policy ban, many Victorian towns along the Murray River effectively drink recycled sewage already, by taking their drinking supplies from rivers that are boosted by the treated wastewater of towns upstream.