Using rainwater after a bushfire and the use of fire retardants

Using rainwater after a bushfire

The following information is provided to residents where rainwater tanks may have been contaminated either indirectly by ash, smoke, debris or directly by fire and fire fighting activities.

How can I tell if my rainwater tank has been contaminated?
Assume that your rainwater is contaminated if it:

  • tastes or smells unusual
  • is cloudy
  • has an unusual colour
  • contains debris, or
  • if the water level has changed (increased).

Do not use contaminated rainwater for drinking, prepare foods, making ice, washing, bathing or cleaning teeth (or watering animals)— until it is tested by a National Association of Testing Authorities (NATA) accredited chemical laboratory—if:

  • you think that your roof was covered by fire suppressant water either dropped by aircraft or sprayed from ground units
  • your rainwater has become contaminated by ash
  • your rainwater tank has been burnt by fire and the internal lining material is damaged
  • if the plumbing to or from the tank is damaged.

For further information about the use of firefighting retardants, click here.

You can use contaminated rainwater for

If you think that your rainwater tank has been contaminated by either of the ways mentioned above, you can still use the water to:

  • flush toilets
  • water the garden
  • wash clothes (providing it will not stain clothes)
  • wash cars
  • fight fires.

Care should be exercised before using any contaminated rainwater to fill swimming pools or in evaporative air conditioners as ash and other debris may clog filters and pumps. Contact the manufacturer for more advice.

Can I treat rainwater if it has been contaminated?

No, it is extremely difficult and potentially 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.

First rains

It is important for residents in fire affected areas or in areas where ash may have fallen on roofs to ensure that all rainwater from the first good rain fall event is not collected as this may be contaminated by ash.

Source:  adapted from information provided by Western Australia Department of Public Health