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Pools and water tanks


After a flood disaster you’ll need to restore your swimming or spa pool before it’s safe to use again. It’s likely that pools contaminated with floodwater will contain harmful germs and may also become breeding sites for disease-carrying mosquitoes.

Things to consider

Pool fencing

Damaged fencing must be fixed as soon as possible and meet the pool safety standards.

Electrical safety

If you know, or suspect, that flood waters have affected your pool’s electrical equipment, have a licensed electrician inspect and declare it fit for use before you try to use it.


If you can’t restore your pool soon after the disaster make sure that you take action, as soon as is safe, to prevent mosquitoes from breeding in the water. Find out how you can reduce mosquito borne diseases.

Restoring water quality

Contact your local council about disposing of the contaminated water, as certain regulations may apply.

Contact your local pool shop for advice on when you can pump out the water without causing damage to the pool structure. They can also give you advice on the best way to clean, sanitise and refill your pool, and re-establish water quality so your pool is safe to swim in.

After the pool has been emptied you’ll need to clean and sanitise the entire pool, including the surrounding structures and associated plumbing and treatment equipment.

Water tanks

Rainwater tanks and bore water holding tanks impacted by floods are likely to contain harmful organisms. The water in the tanks is not suitable for normal use.

Things to consider

Safety assessment

Check the structure of your tank and the surrounding area before you begin restoration works. If the tank has been damaged or relocated, it can be a drowning risk. Restrict access to the tank to reduce the hazard.

Electrical safety

If you know, or suspect, that flood waters have affected your water tank’s electrical equipment, have a licensed electrician inspect and declare it fit for use before you attempt to restore it.


It’s the law in Queensland for all openings on water storage tanks to have:

  • mosquito-proof screens that have all of the following characteristics
  • are made of brass, copper, aluminium or stainless steel gauze
  • have a mesh size of not more than 1mm
  • are installed in a way that does not cause or accelerate corrosion
  • stop mosquitoes passing through the openings


  • flap valves that, when closed, stop mosquitoes passing through the openings.

Damaged tanks that are missing screens or flap valves are ideal breeding sites for disease-carrying mosquitoes. As soon as is safe to do so, take action to prevent mosquitoes from breeding in your water tanks. Checking the integrity of water tank screens and replacing damaged screens is a sound prevention measure.

Reinstating your rainwater or bore water holding tank

First you’ll need to empty your tank of water. If you have an underground tank, don’t attempt to empty it while the surrounding ground is still wet. This can damage the tank and its plumbing.

Once the tank is empty, hose out the inside with clean water and sanitise. Any plumbing, guttering, downpipes and roof surfaces will also need to be cleaned and sanitised.

Contact your local water tank supplier for advice on the best sanitation method for your tank. You may need to hire a professional tank cleaner.

If cleaning of the tank requires entering the tank, it is recommended that a qualified, professional tank cleaner undertake this activity as working in a confined space is hazardous. Cleaning agents that release hazardous fumes or adversely affect the water quality after cleaning should not be used.

After the tank is clean and sanitised, refill it with water from a safe source and disinfect it using enough chlorine to give an initial chlorine dose of 5mg/L. You’ll need to calculate the amount of water in your tank to determine the right amount of chlorine to put in.

The amount required will depend on what form of chorine you use. However, as a general rule:

  • household bleach (4% concentration): 125 ml or 125g per 1000 litres
  • liquid swimming pool chlorine (12.5% concentration): 40 ml or 40g per 1000 litres
  • granular swimming pool chlorine (70% concentration): 7ml or 7g per 1000 litres.

Always follow the warnings, directions for use and safety precaution advice on the chlorine product label.

After you add the chlorine, allow the water to stand for at least one hour (or overnight if possible).


For assistance with a life threatening situation phone 000 (triple zero) immediately.

For assistance with non-life threatening situations - such as help with a damaged roof, rising flood water, or storm damage - phone the SES on 132 500.

For information and support phone the Community Recovery Hotline on 1800 173 349.

Stay up-to-date on Facebook at @qldcommunities or Twitter @RecoveryQld.

Creative Commons Attribution 3.0 Australia (CC BY 3.0)
Last updated:
8 December 2015
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