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Important Facts for OSSF Owners

What is an On-site Sewerage Facility?

On-site sewerage facilities (OSSF) consist of wastewater systems situated within property boundaries that treat the sewerage generated from the property and the land application area of the treated effluent.

OSSF include all types of wastewater treatment and land application, such as septic tanks, aerated wastewater treatment systems, biofilter systems, composting toilets, and activated sludge systems.  These systems are required in areas not served by sewerage infrastructure.
Effective on-site treatment and land application achieves:

  • Protection of public health and safety
  • Maintenance and enhancement of environmental quality
  • Maintenance and enhancement of community amenity

The property owner is responsible for ensuring maintenance is carried out on their system.

Council performs regulatory functions regarding new installations of OSSF, additions to existing systems, effluent run-off complaints, list of licensed service persons, site and soil evaluators and auditing and monitoring.

Site and Soil Evaluator

One of the important aspects of an on-site wastewater management system is the requirement for a thorough site and soil evaluation to be undertaken as part of the process of obtaining Council approval for effluent disposal within the property. It is essential for the evaluator to select the most suitable on-site effluent disposal facility for the property and engage best environmental practices to support his or her design. The quality of effluent from an OSSF is a key consideration to determine how sewerage effluent is to be controlled and disposed of within the property. Before lodging an application to install, extend or remove an OSSF with Council, it is recommended that the property owner consult with a site and soil evaluator to discuss the options available for effluent disposal within the property.

Commissioning Certificate

Following the installation of a wastewater treatment plant, the manufacturer of the plant is to certify that the facility conforms to design requirements and specifications and that such equipment has been installed and commissioned in accordance with manufacturer’s instructions.

Risk and Benefits

Poorly operated and maintained facilities can pose a high risk to public health and have the potential to create extensive environmental harm.  However, owners of properly maintained systems benefits from more efficient systems with a longer life, increased property values, reduced health risk and improved environmental quality.


Compliance with the Plumbing & Drainage Act 2018, subordinate legislation, QLD Plumbing & Wastewater Code, AS/NZS 1546 and AS/NZS 1547.

Maintaining Your System

Maintenance requirements differ depending on the type of system you have.  State legislation require that aerobic wastewater treatment plants be serviced every three months and aerobic sand filter treatment systems annually. A licensed service agent must be engaged by the property owner to carry out the maintenance and to advise Council of the performance of your system. Service agents will normally conduct the following:

  • Maintenance to mechanical equipment
  • Check accumulated sludge levels
  • Check irrigation system operation
  • Add chlorine and check operation of the disinfection system
  • Removal of sludge and scum from the clarifier/final chamber

De-sludging Your System

Periodic removal of accumulated sludge and scum from the primary treatment section of your OSSF is required to be carried out by a licensed waste contractor.

Be a Good Neighbour

Effluent must be disposed of within the boundaries of the property from which it was generated.  It is an offence to dispose of effluent run-off or spray drift onto adjoining properties.

OSSF Service Agents

For a full list a service agents, search the yellow pages under “Waste water & sewerage treatment”.

OSSF Approved Systems

For a list of approved systems go to Queensland Government Department of Housing and Public Works website or contact them on 13 74 68.      

Related Items

Articles Of Interest

  1. On-site Sewerage Facilities (OSSF)
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