Pure water wasted

The crisis of water supply to our cities is now of tragi-comic dimension.

A grandstand of politicians of all persuasions offers ever bigger engineering fixes. Proposals include massive new dams, large-scale water recycling, new pipelines and costly desalination plants.

None can be readily implemented; all are expensive; none will help cities cope with climate change; all have major environmental consequences. Each, in short, is a mirage.

The proposals all seek to maintain or increase the supply of potable (drinking quality) water. The reality is that 90 per cent of water used in households need not be of that quality.

In Australia, using potable water to flush a toilet is disturbingly wasteful. When this practice began in the 1880s there was a ready supply of potable water for the then attractive novelty of body waste disposal. Things have changed substantially since then.

Southeast Queensland now faces a crisis that exposes the flawed thinking that shaped our historical approach to urban infrastructure, especially for water and sewage.

There are, however, straightforward technological and behavioural changes that can help us out of the water shortage mess. Australian water authorities need to overcome their entrenched scepticism and resistance towards these changes.

Brisbane's demand for potable water could be greatly reduced by using dry composting toilets and or by using on-site treatment and recycling of grey water to flush toilets.

Using on-site recycling of grey water or rainwater in the laundry could significantly reduce use of potable water. Bathroom use, including showers, accounts for about a quarter of household water consumption.

Grey water from the bathroom could be treated and stored on site for use in the laundry, for toilet flushing or garden watering.

Recent attempts at changing water consumption have had limited success because they do not attack the problem in a fundamental way.

Increasing the price is one common approach to reducing consumption. This misunderstands the nature of water demand and the way it is affected by cultural and behavioural factors such as fashion in hair care and clothing. It also overestimates the public's ability and willingness to reduce basic water-using activities, such as bathing and domestic cleaning.