About non-potable water

The difference between potable and non-potable water

Potable water is water of a quality suitable for drinking, cooking and personal bathing. The standards that define potable water are described in the Australian Drinking Water Guidelines.

Non-potable water is water that is not of drinking water quality, but which may still be used for many other purposes, depending on its quality. Under the Workplace Health and Safety Act 1995 non-potable water is a 'substance' for which manufacturers, suppliers and end users have obligations in regard to risk management.

What is recycled water?

Recycled water is any water that has been used at least once and then supplied for reuse, either treated or untreated. Without appropriate treatment, recycled water may contain a range of contaminants.

For example, water used for the final rinse in a commercial laundry is only lightly contaminated and thus may be used again, untreated, for the first wash cycle. On the other hand, sewage must be treated at a sewage treatment plant before it can be recycled for any purpose.

In Queensland, recycled water from sewage treatment plants is put into different classes depending on its microbiological quality. These classes range from Class A+ (the highest) to Class D (the lowest). Recycled water can even be treated at an advanced water treatment plant so that it meets drinking water standards. This is then called 'purified recycled water'.

The difference between non-potable water and recycled water

Recycled water that has not been treated to the level of purified recycled water is just one form of non-potable water. But there are many other types of non-potable water, including stormwater, dam and creek water, bore water and even rainwater collected in rainwater tanks. If non-potable water is adequately treated, its quality will improve and it can be used for a wider range of purposes.

Unless water is known to be of potable quality (e.g. from a drinking water supply system) it should be regarded as non-potable and used appropriately.

Some examples of non-potable water used at workplaces are:

Class A recycled water from a sewage treatment plant used for dust suppression, car washing, landscape irrigation or irrigation of sporting ovals
Rainwater from tanks used for various workplace uses, e.g. cooling towers and car washing
Quarry water used for dust suppression and landscape irrigation
Swimming pool backwash water used for toilet flushing
Agricultural waste water used for crop irrigation
Creek, dam, and river water used for dust suppression.