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Installing a wastewater system – Effluent disposal

Onsite disposal of wastewater is required in areas where reticulated sewerage is not available.

You must apply online every time you intend to construct and install an apparatus for on-site wastewater disposal.

This requirement is in accordance with the Health (Treatment of Sewage and disposal of effluent and liquid waste) Regulations 1974.

All applications are submitted to the City of Canning. Approval depends on the proposed system:

  • If the proposed apparatus will handle less than 540L/day of wastewater OR the building to be serviced is a single dwelling, the City of Canning will process and approve your application.
  • If the wastewater volume generated is more than 540L/day AND the building being serviced is not a single dwelling, then the City will assess your application, prepare a local government report, and forward the application to Department of Health WA for approval.

All applicants must:

  • complete and sign the application form submitted online
  • pay the fee – required upon online submission.

The following technical information is also required in the application:

  • Type of the development.
  • Description of staged development, if planned.
  • Size of served facility.
  • Intended use of the building and the intended use of rooms within the building.
  • Proposed installation and methods of disposal/reuse of the final effluent.
  • Site and Soil Evaluation. It is strongly recommended that professionals be engaged to undertake a Site and Soil Evaluation (that is, persons with tertiary qualifications in soil sciences, hydrology, engineering or similar). The evaluation should be carried out in accordance with AS/NZS 1547: 2012 On-site domestic-wastewater management and the Guidance on Site-and-soil evaluation for Onsite Sewage Management (PDF 160KB).
  • Plans and specifications. A detailed plan of the on-site wastewater system, site plan and a building plan must be submitted. All plans are to be drawn to a scale of not less than 1:200.
  • Design details of the system.
  • Description of treatment process.
  • Flow and load of effluent:
    • maximum number of persons using the system/occupancy rate
    • type of facility to be served and per capita daily wastewater flow rate
    • total hydraulic load
    • calculation of daily wastewater volume
    • composition of wastewater, for example:
      • blackwater
      • greywater
      • non-domestic characteristics.
  • Detail quality of effluent, both before and after treatment, shall be demonstrated prior to land application or discharge.
  • Details of land application or reuse system.
  • A signed maintenance agreement between the owner and the service provider must be submitted for:
    • ongoing servicing
    • pump out
    • emergency repairs.
  • Regular maintenance of any systems must be detailed in the maintenance agreement, including frequency of maintenance and methods. The property owner will be held responsible for the ongoing operation of the system and should make any tenant aware of their responsibilities. This requirement does not apply to conventional septic tank systems.
  • Certified engineering specification of commercial wastewater treatment plants and treatment ponds must accompany applications where these are proposed.

Incomplete applications will not be progressed until all required information has been provided. The City can only assess complete applications.

Yes, there is. Refer to the application form for the latest fees and payment instructions.

Yes. Please view the list of approved wastewater systems.

Only approved wastewater systems can be used in WA. The Department of Health requires certification of onsite wastewater treatment systems against the relevant Australian Standards. Premise owners who install an unapproved system breach the Health (Treatment of sewage and disposal of effluent and liquid waste) Regulations 1974.

Any on-site effluent disposal systems must be decommissioned once a property is connected to the sewer.

Septic tanks must be decommissioned to prevent them from collapsing in the future to avoid causing damage or injury. Under law, decommission septic tanks if any of the following applies:

  • If ownership of the property has changed. New property owners are responsible for ensuring that septic tanks are decommissioned. Having proof of the decommissioning is recommended. This process is often negotiated during property settlement.
  • If the building foundations will be built closer than 1.2 metres from the septic tank, or if a building is to be constructed above it.
  • Before any building works start.
  • Within 60 days if there is a ‘material change of use’ of the property. For example, if a residence becomes a business, decommission the system no more than 60 days after the change of use has occurred.

Decommissioning means that:

  • Septic tanks, leach drains, and soak wells must be completely emptied by a licensed liquid waste contractor.
  • Empty septic tanks, leach drains, and soak wells should be completely removed from site if possible. If it is not possible, remove lids and break up the bottom of septic tanks.
  • The excavations, septic tanks and leach drains or soak wells have clean fill such as yellow sand. They have then been thoroughly compacted.
  • Only licensed and approved personnel can decommission septic tanks. Visit the Yellow Pages for a list of septic tank removal companies.

Those considering purchasing a property should determine if decommissioning has already occurred. This is important due to the costs associated with decommissioning.


The City requires a statutory declaration from development or subdivision applicants confirming all septic systems have been decommissioned. The statutory declaration must be provided before the City approves such applications.

If you are decommissioning a system, it is best to complete a statutory declaration when this occurs in case you need it for future applications.

Download an example statutory declaration form (PDF 100KB).

To learn more about the wastewater system requirements, visit these websites:

Government Sewerage Policy

The WA Government’s Government Sewerage Policy outlines the provision of sewerage services during the planning and development of land. It requires reticulated sewerage be provided during the subdivision and development of land.

When reticulated sewerage cannot be provided, the policy requires a best practice approach to the provision of on-site sewage treatment and disposal.

Please download the Government Sewerage Policy (PDF 1.3MB) to learn more about the requirements.

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