Water monitoring, treatment and testing

Like any source, water from a bore can become contaminated any time with things we may not be able to see, taste or smell. 

Spring water and bores less than 10 metres deep are at the highest risk, and bores over 30 metres deep are likely to have less risk. Check with your regional council or your well driller to learn about the depth of your bore.  

Risks to ground water  

• A poorly covered or maintained bore could lead to contamination entering the water you’re collecting.  
• Farm animals nearby could disturb infrastructure protecting the bore and let contaminants in.
• If the top of the bore is covered by flood water, it’s possible for silt, animal waste, soil and harmful microscopic bugs to seep in.
• Because water is coming from underground, bores can be contaminated by nearby activities and infrastructure including sewage disposal fields, effluent discharge, underground storage tanks, waste ponds, landfills, offal pits and pesticides.

How to monitor and prevent contamination  

• Make sure the bore is sealed, with no holes where contamination could enter through rainwater or surface water. You can concrete around the bore to protect it.
• Fence to keep animals at least five metres away from bore infrastructure like pumps, covers and casing.  
• Be aware of how land around your source water is used and any risks connected with activities or infrastructure.  
• Use an effective treatment system with filtration and UV light. 

Roof water is exposed to risks.   

Risks to roof water  

• Poo from animals like birds or possums could be washed off the roof and into storage tanks when it rains. 
• A bird, mouse or other small animal could get into a storage tank if it isn’t secured and kept in good condition.   
• Tennis balls or similar on the roof can block downpipes and interrupt water supply.   
• Wind can carry contaminants like herbicides or pesticides onto the roof. 
• Sediment building up at the bottom of a tank could contain harmful microscopic bugs.
• If there is lead in nails, paint or other roofing materials, toxins could leach out into water.      

How to monitor and prevent contamination  

• Keep your roof clean.   
• Try to prevent birds and animals from accessing the roof or getting into tanks. This could include cutting back any overhanging branches. 
• Clear leaf screens and flush diverters after rain.  
• Check there are no gaps or holes in tanks. 
• Keep tanks clean.
• Make sure materials used in roofing are lead-free.
• Use an effective treatment system with filtration and UV light.

Surface water is exposed to risks and needs to be monitored.   

Risks to surface water  

• Farming nearby could mean poo from animals makes its way into water.
• People swimming or boating upstream of the water intake could poo, dump waste or disturb silt.  
• Heavy rain could wash poo and soil into waterways and cause cloudiness from disturbed dirt, called turbidity. If water is too turbid or coloured, filters and UV treatment can’t do their jobs properly.
• Logging or land clearing could cause soil to slip into water, increasing turbidity and colour.
• Blue-green algae can introduce toxins that are dangerous to people and animals. Treating or boiling water does not remove these toxins. In the short term, a new source of water is needed to prevent illness.
• Pipes carrying wastewater or stormwater could introduce contamination.    

How to monitor and prevent contamination  

• Check your water source and surrounding areas often and keep an eye out for any changes that might bring risk.
• If cyanobacteria are present, assess the risk of toxins in the water and respond quickly to protect public health. Treating or boiling water does not remove these toxins.
• Use an effective treatment system with filtration and UV light.
• Make sure your treatment system is equipped to manage turbidity, colour and other contaminants which can prevent UV disinfection from working.

If your turbidity is high, one 5-micron cartridge filter might not be enough to clear the water of dirt and other particles. 

Extra cartridge filters installed ahead (upstream) of the 5-micron filter will help to reduce turbidity so UV light disinfection can reach and inactivate all harmful bugs. Extra filters with a larger pore size can be used to catch larger particles.

If your source water is very turbid, you might need to install a filter that uses sand, gravel or other media. These filters catch solid particles like dirt and debris floating in water.

If your turbidity is high, a storage tank installed ahead (upstream) of other treatment equipment can give larger particles of sand, silt and dirt a chance to settle to the bottom, if you take water from above this using floating or raised suction this will reduce the number of particles passing through your water supply.

An AVG filter system is a series of tanks that catch and remove solid particles (usually only used for large supplies serving over 500 people). The system is installed ahead of other treatment equipment. The system is low-maintenance and doesn’t rely on electricity or pumps.

Also called an ion exchange filter, a softening device uses resin beads to trap minerals and metals and exchange them with sodium or potassium. Softeners use salt to clean themselves regularly, a softener will stop working if salt levels aren’t maintained.

A softener can enable proper treatment and extend the life of UV lamps.

An activated carbon filter adsorbs discolouration and can improve the odour and taste of water.

If water is piped somewhere else for use after treatment (e.g. to other buildings or to provide water for stock) there’s a risk that water carrying contaminants like germs or chemicals could flow backwards into your drinking water. A backflow prevention device stops water from flowing the wrong way through pipes. 

There are two main types of backflow prevention device. 

• Air gap backflow prevention. If you have a water storage tank, an air gap uses gravity to make sure contaminated water can’t make its way back into a drinking water supply. The tank’s overflow outlet should be checked regularly to ensure it is clear and the air gap is still effective.  
• Valve backflow prevention. A valve (e,g. double check valve or reduced pressure zone device) is installed as a connection between pipes. The valve has physical barriers to stop water moving backwards.