Drinking water can be sourced from:
- surface water such as rivers, streams or reservoirs
- groundwater
- a combination of both.
The source of your drinking water depends on where you live.
Water is treated to drinking water standard by your water corporation before it reaches your tap. This follows the requirements of:
Some areas rely on other sources for drinking water – for example:
- tank water
- untreated surface water.
Even where mains water is available, some people use groundwater from private wells.
Depending on the quality of groundwater, you can use it for:
- drinking water
- irrigation for crops, domestic gardens and parks
- livestock water supply
- commercial and industrial purposes
- recreational purposes, such as filling swimming pools
- geothermal heating and energy.
In some areas, groundwater might be fresh, but it might be unsafe to drink because of naturally occurring constituents – for example, elevated levels of arsenic.
If you're living in an area with contaminated groundwater, you need to understand:
- what you can and cannot use the water for
- what risks the contamination may pose.
An example of risk is when volatile contaminants, such as fuels and solvents, migrate through the soil as vapour. This vapour can risk health if inhaled.
Drinking contaminated groundwater can affect your health in different ways. It depends on the contamination present.
If you have – or suspect you have – contaminated groundwater at your site, you have a duty to manage it. This duty applies regardless of who caused the contamination.
Check for groundwater contamination
Many activities can contaminate groundwater. Commercial, mining, industrial and agricultural sites are the most common sites where you'll find contamination.
You may also find contaminated groundwater in townships or houses that rely on septic systems. Nearby septic systems can affect groundwater quality in bores servicing houses. This can be common in regional areas.
Researching how a site has been used in the past can help you identify the potential for contamination. It can also indicate the types of contaminants that may be present. To learn about ways to research a site's history, visit Reduce your exposure to contaminated soil.
Check Your Groundwater areas
A Check Your Groundwater (CYG) area is an area or precinct where we know groundwater has been contaminated by:
- an activity
- waste
- pollution
- contaminated land.
You can look up CYG areas on Victoria Unearthed to see how to safely use the groundwater.
Test groundwater before using it
Bore owners are responsible for making sure the groundwater they use is fit for the intended use.
If you want to use groundwater for drinking, irrigation or recreational purposes, it's important you understand the risks associated with the intended use.
It's especially important to understand water quality risks before using groundwater for:
- drinking
- cooking
- cleaning teeth
- bathing
- other personal uses.
You should get the groundwater tested for contamination before you use it. It’s important to re-test water often, as its quality can change over time.
To get your groundwater tested, consult a qualified consultant or a National Association of Testing Authorities accredited chemical analysis testing laboratory. You can find one by searching online or contacting your water authority.
Learn more about testing for contamination on the Department of Energy, Environment and Climate Action website.
Treat groundwater before drinking it
Before use, groundwater may need to be disinfected to remove harmful microorganisms. Depending on its quality, it may also need to be treated to remove harmful contaminants.
A common issue in groundwater is iron. While not necessarily harmful to human health, iron can affect taste and be a significant nuisance. Iron can:
- cause staining – for example, on clothing, sheets, washing machines and basins
- coat foliage and affect plant health
- most commonly, cause fouling of bores, pipes, pumps, storage tanks and faucets.
Another common issue in groundwater is hardness. Hardness can cause kettles and hot water services to scale, reducing their longevity.
You need to understand the water quality to determine the appropriate level and form of treatment required.
There are some off-the-shelf treatments available to manage some common water treatment issues. However, we recommend you consult a professional. They can design a specific water treatment for your site's groundwater quality.
Some treatments may use hazardous chemicals or generate a by-product that requires management. For example, desalination generates a brine by-product.
Even after it's been treated, it’s important to re-test groundwater regularly, as its quality can change over time.
To learn more about untreated water and protecting your health, visit:
- Water quality in tanks, bores and dams on the Better Health Channel website
- Groundwater on the Department of Health website.
Shallow groundwater
In some areas groundwater may be shallow. Shallow is less than 3 metres below the surface.
Shallow groundwater may be a risk if you live in a CYG area or an area where historical land uses may have resulted in groundwater contamination.
If you intend to use the water for a sensitive use, such as drinking:
- check the CYG record on Victoria Unearthed
- stop using the water immediately for anything listed as an unsuitable use
- get the water tested to confirm if it’s suitable to use.
If testing shows the water is not suitable for its intended use, either do not use it or treat it before use.
Avoid direct contact with shallow contaminated groundwater. We recommend you wear protective clothing. Be careful when:
- digging holes for planting or posts
- digging trenches or deeper excavations
- maintenance workers are installing utility services and/or doing repairs
- there's any incidental direct contact – for example, with a leaking basement or wet wall basement.
We recommend you talk to a qualified environmental consultant with groundwater expertise.
Businesses relying on private water supplies
By law, businesses or community groups that rely on a private water supply – such as groundwater – for drinking water must make sure the water meets quality standards.
The Department of Health has advice on private drinking water. It also has guidelines for food and accommodation businesses to make sure the water supply is safe for food preparation and human consumption.
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