Water – Private Drinking Water

Private drinking water supply risks and hazards

Water quality fluctuates even with well-maintained systems.

Harmful microorganisms (pathogens) and chemicals are not visible to the naked eye and may be present in water that appears to be clear. Drinking water containing these contaminants can cause illness such as mild to severe gastroenteritis.

Children, elderly and people with suppressed immune systems are more vulnerable to contaminants and extra care should be taken to ensure the water provided is safe for drinking.

This chapter provides an overview of common contaminants and means to minimise the risk they pose to private drinking water supply systems.

Additional general information can also be found on the Department of Health Water page.

Rainwater contamination hazards

Rainwater can be contaminated by a range of sources. These can include:

• roof materials such as roofs coated in bitumen products or lead-based paints
• animal faeces
• leaves and debris
• ash and chemicals from wood heaters (for example, in instances where chimneys and flues are not installed properly or the burning of inappropriate fuel)
• wind-borne or aerial spraying of pesticides and fertilisers.

Ways to minimise risks to rainwater supply systems

Schools are encouraged to take practical measures to minimise risks to rainwater supply systems, including:

• ensuring the roof surface is suitable for collecting rainwater (i.e. not coated in bitumen products or lead-based paints)
• maintaining and regularly cleaning gutters
• installing leaf stoppers
• light-proofing the tank and plumbing to minimise algae growth
• installing a first flush device to prevent the most contaminated rainwater from entering the tank
• securely covering the tank
• mounting TV antennas off the roof
• removing overhanging branches
• disinfecting water to remove most disease-causing microorganisms, for example, chlorination
• drain for periodic tank desludging.

Bores (groundwater) contamination hazards

Bores (groundwater) can be contaminated by a range of sources. These can include:

• sewage
• animal faeces
• industrial and agricultural run-off (such as pesticides and fertilisers)
• seepage from rubbish
• polluted stormwater
• chemical spills and fuel from pump
• naturally occurring chemicals (such as arsenic)
• infiltration with contaminated surface waters and flood waters.

Ways to minimise risks to bores (groundwater supply systems)

Schools are encouraged to take practical measures to minimise risks to groundwater supply systems, including:

• surrounding the bore with a concrete slab sloping away from the bore casing for surface drainage
• ensuring the bore cover is securely in place to prevent entry of pests and contaminants
• mounting the pump on a separate concrete slab with bunding
• fencing the bore off to prevent access
• filtering the water to remove contaminants
• light-proofing the tank and plumbing to minimise algae growth
• using ultraviolet disinfection to remove most disease-causing microorganisms
• installing screens on all tank inlets, outlets and vents
• securely covering the tank
• maintaining a buffer distance between the bore and onsite wastewater system
• locating onsite wastewater system downslope of bore.

Natural events

During rain events water can be washed from other sources into rainwater tanks and move water underground, affecting bore water.

If dust is blown onto your roof and is washed into your rainwater tank, chemical residues can build up in the water.

If your school is in a bushfire affected area your private drinking water could be contaminated from debris, ash, dead animals, aerial fire retardants and water-bombing

Stagnant water

During prolonged shutdown periods (such as school holidays) water sitting in pipework can cause leaching of metals which may impact water quality.

Following a shutdown period, schools should run a tap furthest from the supply source for 2 to 3 minutes. Flushing for longer may be needed for larger water systems. This should be done before students and staff return to school.

Rural water

It is crucial that schools do not mistake rural water for urban water. Rural water is untreated water used for irrigation or toilet flushing, not for drinking. Some schools may mistakenly believe that drinking water is available through mains because rural water comes from streetside water authorities. Only urban water can be used for drinking purposes.