Wastewater systems

Onsite disposal of wastewater is required in areas where reticulated sewerage is unavailable.

Every onsite wastewater system requires an approval.

Which system to install?

In most cases conventional septic tank leach drain systems will be adequate. 

Your local government may require systems that can produce treated wastewater with a high quality, such as: Secondary treatment systems (STS),  Aerated wastewater treatment systems (AWTS) and alternative treatment systems (ATS). Where nutrient retention is required, the local government should be consulted to determine if the system's nutrient removal capacity will meet their requirements.

There are other approved non-conventional systems that can be used to treat and dispose of wastewater onsite, such as:

  • composting toilets
  • incinerating toilets
  • greywater systems.

Building construction sites are required to have approved temporary toilets if there is no access to toilet facilities onsite.

Understanding Primary Treatment Systems (septic tank systems)

Historically most unsewered developments in Western Australia use Primary Treatment Systems (PDF 453KB) to treat and dispose wastewater.  

More information

Environmental Health Directorate
Department of Health
Telephone: 9222 2000
Email: ehinfo@health.wa.gov.au
Last reviewed: 21-10-2020
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Public Health