Septic tanks – waste water disposal, installation and decommissioning

Septic tank systems provide a method of on-site wastewater disposal that can be used to allow development of land where deep sewerage is not available.

Most of the City’s suburbs are now connected to the deep sewerage system. Older sections of Mullaloo, Burns Beach, Sorrento as well as parts of Marmion and Duncraig, were developed before deep sewerage was available. Those suburbs and properties utilised septic tank systems for wastewater disposal. Most of these suburbs have since been provided with deep sewerage as part of the Water Corporation’s Sewerage Infill Program, however it is possible that old septic tanks may still be in the ground.

In the area of Kingsley between Lake Goollelal and Wanneroo Road and a very small pocket of properties located in Joondalup, deep sewerage is still not available and the properties in those areas use septic tanks or alternative on-site effluent disposal methods such as Aerobic Treatment Units for wastewater.

Buildings, foundations and most structures are not permitted within 1.2m of septic tanks or 1.8m from effluent soak wells and leach drains. Areas above septic tank systems should not be paved unless access to the system is still available without requiring the removal of paving. Septic tank systems can utilise a large area of a property that cannot be built on. This restriction can prevent owners of houses using septic tanks systems from installing pools, retaining walls, gazebo’s and granny flats on their property. Once deep sewerage is available to a property, owners may connect to the sewer and decommission their septic tanks and waste water system.

Installing a septic tank apparatus

The installation of a Septic Tank Apparatus must comply with the Health (Treatment of Sewage and Disposal of Effluent and Liquid Waste) Regulations 1974.

For the steps involved in obtaining approval for a septic tank system, please refer to the Septic tank information sheet (external link) or contact an Environmental Health Officer.

Decommissioning your septic system

Notification to the City should be provided, once a septic apparatus has been decommissioned, by completing and submitting a decommissioning form together with a copy of the liquid waste receipt as evidence of the pumping out of the system.

The form must indicate the number of septic tanks and soak wells or leach drains that were removed.

A septic system and waste water system must be decommissioned within 60 days of a change of ownership, following connection to sewer.

Lodging a decommissioning form

You can lodge a decommissioning form online (preferred): 

Or by completing the decommissioning form and submitting it –

  • In person by visiting the City of Joondalup Administration Centre, 90 Boas Avenue, Joondalup.
  • By Post to the City at PO Box 21, Joondalup WA 6919.