Summary

  • If the water in your tank looks, tastes or smells unusual, assume it is contaminated.
  • Water can be disinfected by bringing it to a rolling boil or by adding accurate amounts of chlorine.
  • If your tank needs cleaning, it is recommended that you contact a specialist contractor, as working in a confined space is dangerous.
  • Water that is not suitable to drink may be used to fight fires or water the garden.
If you live in a bushfire-affected area, you should be aware that your private water source could become contaminated from debris, ash, fire retardants or dead animals. Also, you should not source water from a creek that has been affected by bushfire as the water may be contaminated.

Water drawn from deep bores or wells should still be safe to use. If you suspect contamination, use an alternative water supply for drinking and food preparation. Contact your local council for a list of water carting contractors.

Preventing water tank contamination

The most effective way to prevent contamination of your water tank is to make sure it is properly sealed and to disconnect the downpipes to the tank as soon as there is a bushfire risk. Do not reconnect the downpipes until the roof has been cleaned after the bushfire, either manually or after a flush of rain.

Detecting tank water contamination

If your water looks, smells or tastes unusual, then it is likely to be contaminated. Do not use the water for drinking or food preparation, and do not give it to animals.

Water that is not suitable for drinking can still be used on the garden. Water testing is not necessary, as contamination is easily identified by a change in taste, smell or clarity.

Debris or dead animals on your roof or in the gutters should be removed. Use gloves and place in a plastic bag for disposal. Your tank water should be disinfected before re-using.

Disinfecting tank water

Water can be disinfected by bringing it to a rolling boil or by adding chlorine. For every 1,000 litres of water in the tank, you can safely add either:
  • Approximately 125 ml or 125 g of 4 per cent household bleach. Avoid using bleaches that contain detergents or other chemicals, such as perfumes
  • Approximately 40 ml or 40 g of 12.5 per cent chlorine liquid swimming pool chlorine or dairy factory chlorine
  • Approximately 8 ml or 8 g of 65 per cent granular ‘swimming pool’ chlorine.
After chlorinating, you should wait at least 24 hours before using the water to allow for harmful microorganisms to be treated.

When to resume using your rainwater tank for drinking

If the water in your tank has not been contaminated, the water should be safe to use. However, do not reconnect your downpipes until your roof has been cleaned.

Only clean the ash and debris from your roof and gutters when it is safe to do so.

Do not use the water for drinking if it looks, smells or tastes unusual. The water and tank should be disinfected prior to use.

It should not be necessary to clean your tank after a fire unless it is grossly polluted or smells and tastes unusual as a result of aerial fire retardants.

Alternatively, you can arrange for your tank to be professionally cleaned. Where cleaning involves entering a tank, consider employing a professional tank cleaner. Tanks are confined spaces and can be dangerous to work in. Refer to your local business directory for water tank cleaners.

Where to get help

  • Your doctor
  • Environmental Health Unit, Department of Health, Victoria Tel. 1300 761 874

Things to remember

  • If the water in your tank looks, tastes or smells unusual, assume it is contaminated.
  • Water can be disinfected by bringing it to a rolling boil or by adding accurate amounts of chlorine.
  • If your tank needs cleaning, it is recommended that you contact a specialist contractor, as working in a confined space is dangerous.
  • Water that is not suitable to drink may be used to fight fires or water the garden.
References
  • Private water sources in bushfire-affected areas, Environmental Health Unit, Department of Health Victoria, Victorian Government, Australia. More information here.
  • Rainwater tanks – your private drinking water supply, Environmental Health Unit, Department of Health, Victoria. More information here.
  • Drinking water – water company address list, Environmental Health Unit, Department of Health Victoria, Victorian Government, Australia. More information here.
  • Fire retardants and health, Environmental Health Unit, Department of Health Victoria, Victorian Government. More information here.

More information

Enviromental health

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House and garden

Air and water quality

Bushfires, floods and extreme weather

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This page has been produced in consultation with and approved by: Department of Health and Human Services - Emergency Management

Last updated: September 2015

Content on this website is provided for education and information purposes only. Information about a therapy, service, product or treatment does not imply endorsement and is not intended to replace advice from your doctor or other registered health professional. Content has been prepared for Victorian residents and wider Australian audiences, and was accurate at the time of publication. Readers should note that, over time, currency and completeness of the information may change. All users are urged to always seek advice from a registered health care professional for diagnosis and answers to their medical questions.