Septic Tank Maintenance
Burdekin Shire Council
How to maintain septic systems in the Burdekin
There are three components to a conventional Septic Tank System:
 Sanitary plumbing fixtures which include the toilet, kitchen sink,
dishwasher, laundry trough, washing machine, shower, hand basin and
any other unit connected to a drain that carries waste to the septic tank.
 The septic tank.
 The effluent disposal system.
The Septic Tank
A septic tank consists of a watertight receptacle, designed and constructed to receive sewerage from
plumbing fixtures in the building. Its main role is to separate different wastes through sedimentation and it
also provides digestion of the refined organic matter by bacterial activity.
Three distinct zones exist in the septic tank:
 The sludge zone, where the heavier solid material settles on the bottom of the tank.
 The scum zone, where the lighter residues of grease and soap float to the top of the tank.
 The detention zone, the middle layer containing mainly liquid.
Odours
The septic tank functions correctly when the contents are alkaline. This can be achieved initially by mixing
5kg of hydrated lime (Calcium hydroxide) with sufficient water and flushing this slurry into the septic tank
through the toilet pan. Lime treatment can be utilised at other times when acidic conditions occur inside the
tank. Note: avoid lime coming into contact with skin and eyes, wear eye protection and rubber gloves when
handling this material.
Offensive odours will also result from the use of strong chemical cleaning agents which will kill the bacteria
inside the tank and thus cause the system to malfunction. Always use cleaning agents that are labelled as
suitable for use with septic systems.
Mosquito Control
An incorrectly maintained septic system is the perfect breeding place for mosquitoes. This can be prevented
by:
 Covering all vents with a non-ferrous mosquito proof mesh
 Ensuring covers on inspection openings, the septic tank, pump chamber and effluent disposal system
are sealed to prevent mosquitoes from gaining access.
The use of pesticides intermittently flushed through the toilet pan has been used as a method of controlling
mosquitoes, this will not be necessary if mosquitoes are denied access. An excess of pesticide in the tank
can disrupt necessary bacterial action and cause the unnecessary discharge of pesticide into the environment
and underground water.
Maintenance Tips
DO
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Use only soapy water or biodegradable cleaners to clean toilet and sanitary
fixtures.
Check sludge levels in the septic tank every two years.
Have excess sludge removed from the tank every 3-4 years. (More often if a
food waste disposal unit is connected to the system).
Use toilet paper that breaks down readily.
Restrict food scraps entering the system.
Minimise the amount of water entering the system.
Page 1 of 2
For further information please contact Council’s Customer Service Centre
Phone: (07) 4783 9800
Email: customer.service@burdekin.qld.gov.au
DO NOT
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Attempt to disinfect the septic tank after excess sludge has been removed.
Dispose of sanitary napkins, coffee grounds, tea leaves, cooking fats or oils, bones, disposable
nappies or cigarette butts into the septic system.
Subject the system to hydraulic shocks, e.g. the simultaneous use of washing machines,
dishwashers, baths and showers.
Burdekin Shire Council
AVOID
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Use of strong caustic alkalis, oils, acids, bleaches and disinfectants.
Prohibited Discharges
No person shall permit or cause any of the following discharges to enter a septic tank system:
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Stormwater, including roof and rainwater overflow and surface drainage waters.
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Disposable napkins, clothing or plastic sheeting.
Back-flush waters from a swimming pool or water softener.
Discharge/back-flush from a spa bath/pool in excess of 120 litres, unless the system has been
specifically designed to accommodate such loading.
Trade waste.
Petrol or other flammable or explosive substance whether solid, liquid or gaseous.
Disinfectants or deodorants, antiseptic or germicide powders or liquids unless specified as being
suitable for disposal into a septic tank.
Guidelines for the care of the sub-surface disposal system
Reduce the amount of water discharging into the system by:
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Spending less time in the shower.
Using less water in the bath.
Using a suds-saving / eco cycle on the washing machine.
Minimising water use when washing hands and cleaning teeth.
Installing dual flush systems in toilets.
Minimising water usage in the kitchen, e.g. hand wash dishes instead of using a dishwasher.
Avoiding the use of food waste disposal units.
Ensuring leaking taps are repaired immediately
Protect the sub-surface effluent disposal system from migrating surface and sub-surface waters by:
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Diverting roof, tank overflow and storm waters to the street, water table or an area beyond the
soakage system.
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Avoiding washing cars or watering lawns or gardens adjacent to or above the disposal system.
Installing a diversion trench on the high side of the disposal system to arrest and divert surface and
sub-surface waters away from the disposal area.
Sub-surface soakage relies upon evapotranspiration of the effluent from the surface. It is therefore important
to keep the area free of buildings, structures or other impervious coverings such as concrete paths or
driveways.
Page 2 of 2
For further information please contact Council’s Customer Service Centre
Phone: (07) 4783 9800
Email: customer.service@burdekin.qld.gov.au