Bushfires and effect on tank water

Bushfires generate large amounts of smoke, ash and debris that can settle on roof catchment areas carrying the potential to contaminate rainwater supplies if washed into tanks, as a result of clean-up work, watering a roof as a fire protection activity, or following rain after the bushfire.

If used as part of bushfire fighting tactics, fire retardants or foams can also settle on roofs and represent another potential to contaminate rainwater supplies if washed into a rainwater tank.

While the presence of ash and debris in rainwater may not represent a health risk, it can affect the colour, look and taste of tank water.

If your tank water has a smell, looks or tastes unusual, assume it has been contaminated.

Do not use the water for drinking or food preparation, and do not give it to animals.

Small quantities of water can be disinfected by bringing it to a rolling boil or by adding chlorine. In this case the water and tank are thought to be contaminated the tank should be disinfected prior to use.

Please see the attached link on how to disinfect a tank: https://www.dhhs.tas.gov.au/publichealth/water/drinking/clean_tank

If you live in an area affected by bushfire some tips on effective ways to reduce the risk of contamination to water tank are.

  • Where possible, remove any ash and debris deposited on the roof and gutters by brushing or washing the effected roof area. Before washing the roof ensure any inlet to the rainwater tank is disconnected.
  • Check the roof and guttering for any dead animals and remove if present.
  • Do not collect the first flush of rainwater after the bushfire instead use a first flush diverter between the roof and the tank to prevent ash and other debris from entering the tank and contaminating the water. First flush diverters are generally available from at most hardware stores and rainwater tank suppliers. If you don’t have a first flush diverter, disconnect the inlet from the roof to the tank until ash and debris has been removed.