National water-recycling guidelines will address both health and environmental risks according to an editorial published in the current issue of The Medical Journal of Australia.

The guidelines, initiated by the Environment Protection and Heritage Council and the Natural Resource Management Ministerial Council, and to be developed in collaboration with the National Health and Medical Research Council, are intended to provide a unified approach to water recycling across Australia.

Dr Martha Sinclair, Senior Research Fellow at the Department of Epidemiology and Preventive Medicine at Monash University, said years of drought, water shortages and climate variability are behind efforts to reduce water consumption and find other sustainable ways of using all available water.

"Short term efforts include the use of more efficient appliances and water restrictions but longer term strategies are also needed," Dr Sinclair said.

"The domestic use of alternative water sources - rainwater, stormwater, greywater and sewage - has the potential to expose large populations to pathogens and chemical contaminants unless the water is appropriately treated and managed," Dr Sinclair said.

Rainwater collected from roofs, can be contaminated by animal droppings, dead animals, leaf litter, roofing metal and airborne pollutants. While it can be used for bathing, laundering and watering the garden, it should only be used for drinking if it is clear, smells and tastes good and the roof and tank are well maintained.

Stormwater, which is usually polluted, flows untreated into local waterways. Moves are afoot in New South Wales to use stormwater to irrigate local sports fields, wetlands and parks.

Greywater, which comes from kitchen, laundry and bathroom drains (but excludes toilet water) can be contaminated with phosphates, salt and urine and faeces. Treated greywater can be used for toilet flushing, laundering and subsurface garden watering, but can kill plants sensitive to phosphorus, including Australian natives.

Recycled sewage water can be used to flush the toilet, water the garden, wash the car and outdoor surfaces. It can be used for watering sporting fields and parks, fire control and irrigation. But there are questions about the potential impact of the use of reclaimed sewage water on public health.

"With the exception of good quality rainwater, all of the above water types are unsuitable for drinking. However, if they are supplied to thousands of individual households, incidents of accidental ingestion are bound to occur," Dr Sinclair said.

"There is a pressing need for more rigorous scientific evidence to inform regulation," Dr Sinclair said.

CONTACT:                 Dr Martha SINCLAIR             03 9903 0571 (w)

                                Judith TOKLEY, AMA                        0408 824 306 / 02 6270 5471