Rainwater tanks after a bushfire
Water in rainwater tanks on your property can be contaminated during or after a bushfire, either indirectly by ash, smoke, debris or directly by fire and fire fighting activities.
If there is any risk of contamination, do not use water from your rainwater tank for the following activities:
- preparing foods
- making ice
- washing and bathing
- cleaning teeth
- watering animals.
How can I tell if the water in my tank has been contaminated?
You should assume that the water in your tank is contaminated if:
- your roof is covered by ash or other fire debris
- there are dead animals on your roof or gutters or in your tank
- you think that your roof was covered by fire suppressant water either dropped by aircraft or sprayed from ground units
- the tank has been burnt by fire and the internal lining material is damaged
- the plumbing to or from the tank is damaged
- the water is cloudy, tastes or smells unusual or has an unusual colour
- the water contains debris or ash
- the water level has increased.
You can use contaminated rainwater for some jobs
If you think that your water tank has been contaminated in any way, you can still use the water to:
- flush toilets
- water the garden
- wash clothes (providing it will not stain clothes)
- wash cars
- fight fires.
Using any rainwater contaminated with ash or other debris to fill swimming pools or in evaporative air conditioners may clog filters and pumps. Contact the air conditioner, filter or pump manufacturer for advice.
Other sources of water
Water drawn from deep bores or wells should be safe to use.
Do not obtain water from a creek or stream that has been affected by bushfire as the water may be contaminated.
Ensure that all rainwater from the first good rainfall event after the fire is run to waste, as this may be contaminated by ash and other pollutants from the fire.
Water testing is usually not necessary as contamination after a bushfire is usually obvious.
If you would like test the chemical quality of water in your water tank after a bushfire, contact a National Association of Testing Authorities (NATA) (external site) accredited chemical laboratory.
Refer to the Department of Health Publication, Standard Drinking Water Assay (external PDF 79KB) for further information.
If you need advice about interpreting the results from any water testing after a bushfire, contact the Water Unit of the Department of Health.
Can I treat rainwater to a drinking water standard if it has been contaminated?
No, it is usually very difficult and expensive to remove effectively any contamination caused by fire suppressants or any other potentially harmful by-products caused by ash from burnt bush, plastics and metals.
Refilling your rainwater tank
You may need to drain and refill your tank with water from a commercial water carting company. Before you do, make sure that:
- the tank or any associated pipework has not been damaged by fire
- the tank has been desludged and cleaned, if contaminated, by a specialist contractor.
Do not reconnect your down pipes until your roof and gutters have been cleaned or rainwater from the first rains after the fire has been run to waste.
Make sure that the commercial carting company:
- uses the tanker exclusively for drinking water
- gets the water from a scheme drinking water supply
- has treated the water with at least 1 milligram per litre of chlorine while in transit
- follows the Department’s water carting guidelines (external site)
This publication is provided for education and information purposes only. It is not a substitute for professional medical care. Information about a therapy, service, product or treatment does not imply endorsement and is not intended to replace advice from your healthcare professional. Readers should note that over time currency and completeness of the information may change. All users should seek advice from a qualified healthcare professional for a diagnosis and answers to their medical questions.