On-site sewerage facilities (OSFs)

On-site sewerage facilities (OSFs) are any system that store, treat and dispose of household wastewater and sewage on a property in an unsewered area.

There are a number of different types of OSFs, the most common OSFs are Septic Systems and Aerated Wastewater Treatment Systems (AWTS).

Other types of OSF systems include:

  • activated sludge
  • split black and grey water treatment
  • holding tank with pump-out
  • recirculating sand filter.

For a list of approved systems, see the QLD State Government website.

In line with State Government legislation, property owners are responsible for ensuring their OSFs are properly designed, installed, and maintained to protect the health of their family, the community, and the environment.

Is Council approval required?

Council approval is required prior to OSF installation and any alterations. This is to ensure compliance with relevant legislation and wastewater codes are met. This includes the location, size, and design of the Land Application Area (LAA).

For more information on plumbing approvals refer to Plumbing work.

Septic systems

Modern septic systems are generally an all-waste septic tank with an underground disposal area. All household wastewater is directed into these tanks including the toilet, kitchen, bathroom, and laundry.

Maintenance of septic systems

  • clean the outlet filter in line with the manufacturer's instructions
  • engage a licensed service agent every three to five years to check if the septic tank has an excessive sludge build-up and have it removed
  • a visual check is highly suggested every 12 months to monitor the build-up of waste and the general condition of the tank
  • check for any ponding of water or water leaving the disposal area.

Aerated Systems

AWTS treat household wastewater (sewage and greywater) in a series of tank chambers so it can be used for other purposes such as irrigation on that property.

Maintenance of aerated systems

  • ensuring stormwater run-off does not enter the system
  • monitor power disruptions that can cause pump burnout and system failure
  • service system regularly by a licensed service agent, in accordance with the manufactures instructions and conditions of any Council approvals
  • check for any ponding of water or water leaving the disposal area. 

Land Application Area 

The LAA is the designated area on the property where the greywater from Septic Spilt Systems (an older type of septic system) or the treated wastewater (effluent) from AWTS is disposed of.

Your responsibilities

You are responsible for keeping your OSF in good working order, including taking care of your LAA by :

  • ensuring the system is maintained and serviced in accordance with the manufacturer's instructions and the work is undertaken by an appropriately licenced service agent
  • ensuring the LAA is appropriately designed, including adhering to required setbacks
  • keeping vehicles off the LAA
  • preventing surface runoff from entering the LAA; for example, constructing and maintaining a diversion mound
  • not using the LAA for recreation, growing edible plants or containing pets or livestock
  • mowing grass within the LAA and maintaining surrounding plants to avoid shading
  • monitoring your LAA for unusually bad smells (like rotten eggs), poor vegetation or unusual amounts of darker green grass that could all be signs your system needs attention
  • ensuring the wastewater does not leave your property; for example, position the surface sprinkler so it is irrigating only your property.

Why is it important to have my OSF properly maintained?

An OSF that is not working correctly can cause odours, attract vermin and insects, and pose risks to public health and the environment.

Poorly managed OSFs can impact our waterways by:

  • promoting the growth of algae and aquatic weeds that reduce oxygen in the water and negatively impact aquatic life
  • causing viruses and bacteria, such as Escherichia coli (E. coli)
  • contaminating groundwater.

These can negatively affect how the water is used for drinking, recreation, and commercial purposes.

How can I make sure my OSF is operating correctly?

Regular maintenance can prevent your system from failing.

Signs of an unhealthy system

Early detection of system faults allows steps to be taken to prevent system failure. The following may indicate your system needs attention:

  • toilets and drains become slow draining and/or wastewater is regularly backing up
  • air near the system or disposal area smells unusually bad like rotten eggs
  • water is pooling within or near the disposal area
  • the disposal area has poor vegetation growth or an unusual amount of darker green grass
  • system alarms being triggered (AWTS)
  • further breakdown of the effluent occurs naturally in the soil after on-site disposal (AWTS).

General usage and care tips

Certain products, chemicals, and foreign matter may affect the balance of helpful bacteria within your AWTS/septic tank or cause blockages. Get the best out of your system, by following these tips:

  • use biodegradable products (e.g. toilet paper) and avoid chemicals like ammonia, disinfectant, bleach or pesticide.
  • keep out items like baby wipes, hygiene products, bones, glass or coffee granules
  • do not allow oil, fats or food scraps to go down the sink.
  • use water-saving devices and stagger discharge from washing machines, baths etc as excessive water may temporarily overload the system.
  • keep vehicles off the disposal area.
  • avoid using the disposal area for recreation, growing edible plants, or containing pets.

How can I check if my service agent is licensed?

Use the QBCC search for license details of your service agent.

For more information