Before returning home make sure you have an adequate supply of drinking water with you (e.g. bottled water or water from a town water supply).

Rainwater tanks (and bore water-holding tanks) impacted by storms and floods are likely to contain harmful microorganisms. This mean the water stored in affected tanks will not be suitable for normal use.

The tank water should also not be used if the tank or connecting pipework has been damaged, or where flood water has been in contact with taps or connections within or outside the home.

Last updated: 04 April 2023

If contamination of the tank has occurred or is suspected, the town water supply should be used for all drinking and hygiene purposes. If a town water supply is not available, an alternate water supply should be sourced.

If you know or suspect that electrical equipment associated with your tank has been affected, it is recommended that it is inspected and declared fit for use by a licensed electrician before attempting to restore the tank.

Cleaning rainwater tanks

Cleaning rainwater tanks presents a number of occupational health and safety risks, such as working in confined spaces. It is only recommended that a tank be emptied if it has been inundated by flood water.

Be aware that the structural integrity of the tank may be affected and may require attention. Emptying water before the surrounding ground has dried out may result in damage to the tank and associated plumbing.

If cleaning of the tank requires entering the tank, it is recommended that a qualified, professional tank cleaner undertake this activity. Cleaning water tanks presents a number of health and safety risks, such as working in confined spaces. Further information can be found on Rainwater tanks.

Cleaning agents can release hazardous fumes or adversely affect the water quality after cleaning. A tank supplier will be able to advise on the best sanitation method depending upon the material with which the tank is constructed.

If the tank can be cleaned without entering, empty the tank and hose the inside of the tank out with clean water. Inspect plumbing, guttering, downpipes and roof surfaces for damage. These will also need to be cleaned and disinfected.

Disinfecting drinking water in rainwater tanks

Once the tank has been refilled with clean safe water it can be disinfected with chlorine by adding powdered swimming pool chlorine (calcium hypochlorite, 65 per cent available chlorine) or liquid chlorine (sodium hypochlorite, 12.5 per cent available chlorine). You should not use stabilised chlorine (chlorine cyanurates).

Guidance on levels of chlorine required based on tank size can be found on Rainwater tanks.

Cleaning affected taps

  • After the tank water has been disinfected, flush all associated taps for a few minutes to remove any contaminated water in the plumbing lines.
  • Remove any screens, flow regulators and aerators and thoroughly clean the tap and all parts with hot water and detergent.
  • Apply a mild disinfectant to the tap and its parts.
  • Rinse, reassemble the tap and again run it for a few minutes before use.

For further information

Current as at: Tuesday 4 April 2023