Using bore water safely
Water from private bores is a valuable resource and can contribute significantly in meeting your water needs.
Depending on local characteristics, bore water may be suitable for uses including stock watering, irrigation, flushing toilets and washing clothes or cars. It may also be suitable for showering, food preparation and drinking.
However, bore water can become contaminated by natural processes and human activities. Testing by an accredited laboratory is required to confirm the quality of the water, which may require treatment, depending on the intended use.
Where does bore water come from?
When it rains, water seeps down through layers of soil and rock. We refer to it as groundwater. Rivers, creeks and dams also contribute to groundwater.
As the water moves downwards, it will separate into layers at different depths and in different areas. These are called aquifers, some of which are confined by the surrounding rocks and clays.
Is my bore water suitable for watering?
Just like rivers found on the earth’s surface, water in aquifers will flow in a particular direction. As it moves through the ground, it will dissolve minerals and may also pick up any contamination, such as nutrients, pathogens and pesticides.
Water sourced from deeper, confined aquifers is generally of higher quality than water from shallow, unconfined aquifers, which are susceptible to contamination originating from animals, pesticides and fertilisers and industrial processes
Many garden bores in Western Australia take water from the shallow, unconfined aquifer. This is a good alternative to scheme water, for watering your lawn or garden.
A simple test to check if water from your garden bore is suitable for watering is a field pH test, which can be done with a swimming pool test kit of pH test strips. Bore water with a pH of less than 5 should be professionally tested to ensure it is safe to use.
Before installing a bore in the Perth metropolitan area, first consult the Perth Groundwater Atlas (external site) to identify any groundwater problems in your area. The Atlas can also be used to estimate the depth to water.
You should also check the Contaminated Sites Database (external site) to ensure you are not drawing water from a known contaminated site.
Can I use my bore water for household uses?
Bore water can be suitable for domestic non-potables uses, such as toilet flushing, car and clothes washing, as well as irrigating vegetable gardens.
If bore water is your only water supply, or you rely on it to drink when your rainwater supply runs out, you should test the water at least once a year for chemical and microbiological contamination by a National Association of Testing Authorities (NATA) registered laboratory (external site).
Bore water should never be used for drinking, bathing, watering edible plants, filling swimming and paddling pools, food preparation or cooking unless it has been tested and treated to the extent necessary for the intended use.
Can I fill my swimming pool with bore water?
It is preferable to fill your pool or spa with scheme drinking water because it is treated and safe, good quality water.
If you use bore water, however, you will need to increase the quantity of chemicals you use (especially if the water contains a lot of iron) and this will add to your costs. Bore water may also cause staining, due to the dissolved salts and metals.
Do I need to treat bore water?
It is not usually necessary to treat bore water providing it:
- has a pH greater than 5
- is colourless and odourless and
- will only be used to water the garden, wash cars and flush toilets.
Chlorination is the most reliable way to ensure drinking water is free from microbiological contamination. Refer to the Country Rainwater Collection factsheet for advice on chlorine dosing water storage tanks.
How do I test my bore water?
Contact a NATA-accredited laboratory and ask for a Standard Drinking Water Test (PDF 142KB) for your bore water supply.
Bore water used for domestic non-potable uses, should be measured against the ‘Levels for garden irrigation’ as provided in the Department of Environment Regulation factsheet Contaminated Groundwater – could my garden bore be affected? (external PDF 540KB).
Water intended for drinking, food preparation or showering should be measured against the Australian Drinking Water Guidelines (external site).
The Department of Health is also able to interpret laboratory results and provide you with advice on how to make water safe to drink.
Microbiological and chemical laboratories may also be able to assist you with additional technical advice. However, they are not in a position to provide you with health related advice.
Is bore water protected from contamination?
Bore water can be naturally contaminated by minerals, chemicals, bacteria and viruses. However, human activity usually has the greatest impact on shallow ground water quality as a result of:
- excessive or inappropriate use of fertilizers, animal manures, pesticides and insecticides
- poorly maintained septic tanks and other liquid waste disposal systems
- leaking fuel and chemical tanks
- intensive agriculture, industry or mining
- leaching from waste disposal areas
- accidental spills of chemicals.
Bores operated by licensed water providers such as the Water Corporation (external site) for drinking water are protected from contamination as they are located:
- within aquifers (mostly confined and at depth)
- in areas with restricted development and land usage
- are controlled by catchment management plans.
Can I tell if my bore water is contaminated?
It is not always possible to tell if your bore water is contaminated. Signs of contamination may include:
- unusual taste
- a low pH (acidic water)
- a chemical, sewage, petrol or ‘rotten egg’ smell
- soap suds/foaming around sprinkler outlets
- abnormal colour or sediment
- dying or wilting plants
- animals show a reluctance to drink.
If this occurs contact your local Environmental Health Officer.
Are all bore water contaminants a health risk?
Some contaminants are simply a nuisance as they cause staining, or may have an unpleasant smell or taste. An example of this can be found in some metropolitan areas where iron oxide leaches out of the soil causing a red brown stain on walls and footpaths.
Other contaminants such as nitrate, arsenic, pesticides and petroleum products are of health concern, particularly if bore water is used for drinking, bathing, food preparation or watering of edible plants.
How can I reduce the risk of contamination?
- Ensure your bore is installed with a protective cover and is surrounded by a concrete slab, with the wellhead protruding well above the ground. The slab should slope away from the bore, so that surface water does not drain into the casing.
- Regularly inspect your bore to check for signs of contamination.
- For rural or remote locations, ensure your bore is protected from livestock by perimeter fencing at a distance of 50 metres away.
- Locate the bore at least 30 metres from any wastewater system, such as septic tanks or aerobic treatment units.
- Ensure your bore is constructed by a licensed driller in accordance with the Minimum Construction Requirements for Water Bores in Australia (external site).
- This may also be a requirement of the license issued by the Department of Water for the bore.
- Do not use pesticides near your bore.
- Prevent wastewater from soaking into the soil near supply bores and clean up any chemical spills immediately.
How do I maintain my bore?
- Use a licensed driller who is experienced with the soil and groundwater conditions of your area.
- Inspect your bore (including headworks, casing and pump) for signs of scaling, corrosion or damage.
- Maintain your pump in accordance with the manufacturer’s specifications.
- Measure the depth to the water level in the bore regularly, monthly is preferable. Take the measurement before turning the pump on and again immediately after turning the pump off. The depth of the pump may need to be lowered to keep the pump working properly. If either measurement is observed to be continually dropping over a period of more than one year, this may indicate that the pumping rate is exceeding the recharge rate of the aquifer. Over-pumping can lead to silting and the bore may stop working properly.
- Take a water sample regularly. Allow the bore to be pumped for at least 15 minutes before taking readings of pH and salinity (these can be done with an inexpensive field test meter) at the same time as checking the depth to water. Increased salinity may indicate that over-pumping is introducing salty water from another layer, or there is a hole in the bore casing. This could also mean that contamination is entering the bore that hasn’t previously been considered.
What are some common problems?
Many bores and pumps fail because they are poorly constructed, not maintained properly, or because gradual changes go unnoticed.
Installing and pumping water from a well increases the level of oxygen and nutrients in the well.
Bacteria thrive in these conditions and may form a biofilm, which captures chemicals, minerals, sands, clays and silts.
Iron can combine with oxygen and get trapped in the biofilm and sometimes the biofilm accumulates to the point that it reduces the bore yield.
Bores can be decontaminated and/or unclogged by using a range of chemical and physical processes.
For information on the materials and substances that can be used safely to treat your bore please refer to the Materials and Substances in Contact with Drinking Water factsheet (PDF 686KB).
If the bore fails due to a structural problem, such as blockage, corrosion or collapse of casing materials (including screens), contact a licensed driller who can provide further advice on repair or redevelopment works.
Can I connect my bore water to a scheme drinking water supply?
Bore water cannot be connected to the scheme supply unless:
Do I need a licence to install a bore?
Domestic garden bores in the Perth metropolitan area do not require a licence, as they have been exempted through an Exemption Order under the Rights in Water and Irrigation Act 1914 (external site).
With the exception of Albany and the Exmouth northwest cape section of the Gascoyne groundwater areas, licences are not required for domestic garden bores outside the Perth metropolitan area, as long as:
- they are installed in the shallow, un-confined aquifer
- the water is used only for domestic purposes, firefighting, non-intensive stock watering or garden/lawn irrigation of up to 0.2 hectares (2,000 square metres).
For bore uses which fall outside of the exemption criteria listed above, a licence to construct or alter a well may be required in addition to a licence to take water. Contact the Department of Water (external site) for more information on how to obtain these licences.
How do I decommission a bore?
If a bore is damaged and can’t be fixed or is no longer needed, it must be properly decommissioned.
Filling the bore with grout or bentonite from the top to the bottom is the preferred method of decommissioning. This will eliminate any physical hazard (e.g. open holes) and prevent groundwater contamination.
Environmental Health Directorate
Department of Health WA
PO Box 8172
PERTH BUSINESS CENTRE WA 6849
Telephone: 9388 4999
This publication is provided for education and information purposes only. It is not a substitute for professional medical care. Information about a therapy, service, product or treatment does not imply endorsement and is not intended to replace advice from your healthcare professional. Readers should note that over time currency and completeness of the information may change. All users should seek advice from a qualified healthcare professional for a diagnosis and answers to their medical questions.