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Most South Australians obtain their drinking water from a water authority. However, some people obtain their own water from:
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Rainwater tanks
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Rivers and creeks
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Dams
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Bores
It is important to make sure your private drinking water is not contaminated.
Contaminated water can make you ill
Contaminated water supplies have been responsible for major outbreaks of severe gastric illnesses such as gastroenteritis and infections caused by the Cryptosporidium and Giardia organisms.These illnesses are particularly dangerous to the very young, the elderly, and people with poor immune systems.
Different things can contaminate your water
Your private water supply can be contaminated by a variety of things like:
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Animal faeces – like bird or possum droppings on the roof, or from farm run-off into rivers or creeks.
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Human faeces – leaking from septic systems or waste water drainage.
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Pesticides– in run-off from farms, or blown onto roofs.
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Arsenic and heavy metals – in soil from old industrial or mining sites, or in some bore water supplies.
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Dust – containing chemicals may be blown onto your roof.
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Air pollution - run-off from roofs in urban and industrial areas may contain chemicals.
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Lead – from old paint or flashing on roofs can flake and ends up in tanks.
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Algae – including toxic blue-green algae which is not destroyed by boiling or disinfection.
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Nitrates – in some bore water supplies are particularly dangerous to infants
There are laboratories that can test your water for these things. Look them up under A for Analyst in the Yellow Pages.
Collect and store your water carefully
If you collect and store your drinking water carefully, you can reduce the risk of contamination. You should:
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Make sure surface runoff and leakage from sewage pipes and other drainage cannot enter your water storage
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Seal your water storage so animals, birds and sunlight cannot get in
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Collect water only from clean roofs - not from those painted recently or painted with lead-based paints or coated with tar
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Clean your roof, gutters and water tanks regularly
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Install screens or filters between the supply and storage
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Install a ‘first flush’ diversion - the first rain after a dry period contains most of the contaminants
Disinfect your water supply if you suspect it has become contaminated with sewage or animal faeces.
Some water supplies will need to be disinfected
In most rural areas of South Australia, rainwater collected from a clean roof and securely piped into a well-maintained above-ground tank should not need to be disinfected. Groundwater from a shallow bore should be disinfected in case the water has been contaminated with farm waste or leaking effluent from a septic tank. If your water is dirty or cloudy, you should filter it first because dirt particles can make disinfection ineffective. People with suppressed immune systems should only consume water that has been boiled.
What to do if there’s a dead animal in the tank
A dead animal in your tank will not necessarily cause illness if you drink the water. As a precaution, you should:
- Drain all water from the tank
- Clean inside the tank with household bleach
- Refill your tank with good quality water
- Disinfect it with chlorine
Remember to maintain good ventilation when you clean out any tank and always work with an assistant outside the tank.
Bushfires
Bushfires generate large amounts of smoke, debris and ash. If you live in a bushfire-affected area, you need to be aware that your water tank could become contaminated. Sources of contamination can include dead animals, and debris or ash washed off the roof and into the tank when it rains. Ash and debris may contain chemicals that could be harmful if they get into your drinking water supply, while dead animals can make water unsafe to drink. If there is debris and ash on your roof, the first flush of water will not be suitable for drinking.These contaminants may have already washed into your tank if you have been hosing your roof as part of your fire plan or if it has rained.
Install a first flush diverter
This prevents ash and other debris from contaminating the water. First flush diverters are available from most hardware stores and suppliers of rainwater tanks.
How to tell if your tank water is contaminated
The best guide is your knowledge of what your tank water usually looks and tastes like.
- If the water tastes or smells unusual, is cloudy or discoloured, or contains particles, you should assume it is contaminated. Do not use it for drinking, food preparation or making ice until the tank has been cleaned and refilled with new rainwater or clean water brought in by a water carter
- If there is any doubt, assume the tank water is contaminated
- You may choose to have the tank water tested before deciding whether to use it for drinking. A laboratory analyst can test a sample of tank water for chemical, microbiological and algae levels
- Water that is not suitable to drink may be used for other purposes such as fire fighting or watering the garden
- Do not give contaminated water to animals to drink
The clean up
Regardless of whether your tank needs cleaning or not, you still need to clean the roof to prevent contamination by debris entering the tank. Suggestions include:
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Use the first flush diverter on your tank to divert any residual debris away from your drinking water storage.
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If you don’t have a first flush diverter, disconnect the inlet from the roof to the tank until the roof has been cleaned of debris.
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When safe to do so, arrange to clean debris from the roof and gutters before it rains. Be careful to avoid injuring yourself.
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Dead birds or other small animals found in gutters should be removed using gloves and put in a plastic bag for disposal. Your local council’s Environmental Health Section can advise you about their disposal.
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To clean the tank, first remove any sludge. Then rinse or scrub the interior with a diluted household bleach solution. Use strictly according to the manufacturer’s instructions on the label.
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Do not climb inside the tank unless you can be sure you have good ventilation. Enclosed spaces can quickly become hazardous.
Creeks and streams may be contaminated
Catchment areas may be contaminated following a bushfire. When it rains, debris from the bushfire washes into creeks and streams. This means that water diverted from creeks and streams will not be suitable for drinking. Untreated water from these sources should not be used for drinking. Water from deep bores or wells should continue to be fit for human consumption.
Things to remember
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Contaminated water can cause serious illnesses
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Water that looks clear can still be contaminated
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If the water in your tank tastes or smells unusual, or is cloudy or discoloured or contains particles, assume it is contaminated
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Do not use your tank water for drinking, food preparation or making ice until the tank has been cleaned and refilled with new rainwater or clean water brought in by a water carter
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It is your responsibility to make sure your private water supply is safe
Water that is not suitable to drink may be used to fight fires or water the garden.
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