Government Sewerage Policy (2019)

The Government Sewerage Policy (2019) sets the State Government’s position on how sewerage services are to be provided in Western Australia through the planning and development of land.

Implementation update: Onsite sewage disposal – ‘secondary treatment systems with nutrient removal

Since the release of the Policy, issues have emerged with implementing the requirements for a ‘secondary treatment system with nutrient removal’. All secondary treatment systems need to be tested for compliance with Australian/New Zealand Standards 1546:3 On-site domestic wastewater treatment units Secondary treatment systems (AS1546:3:2017) by the end of 2020. It is unclear how many systems will comply with the nutrient removal criteria contained in the Policy or ASNZS 1546:3:2017.

Until this issue is resolved, any secondary treatment systems listed on the Department of Health website as having a ‘nutrient reduction capability’ are recommended wherever a ‘secondary treatment system with nutrient removal’ is required in the Policy. Consideration should also be given to the capability of available systems to accommodate hydraulic loads and composition of sewerage generated on-site, particularly for non-residential land uses. Further information on the certification of secondary treatment systems is available on the Department of Health website. Any queries should be directed to the Environmental Health Directorate via or phone 9222 2000.

The policy guides future strategic planning, subdivision and development for the provision of sewage disposal in Western Australia.

The policy promotes reticulated sewerage as the best disposal method for sewage. It requires all new subdivision and development to be connected to reticulated sewerage where available or considered necessary on health, environment or planning grounds. 

Where reticulated sewerage cannot be provided, the policy provides detailed site requirements for on-site sewage treatment and disposal.

The policy will replace the Government Sewerage Policy – Perth Metropolitan Region (1996) and Draft Country Sewerage Policy (2002, amended 2003) when operational on 23 September 2019.


The location of Public Drinking Water Sources areas is available for viewing at the Department of Water’s Geographic Data Atlas

Guidance for Site and Soil evaluations for on-site sewage disposal can be found on the Department of Health website.  

If you require additional information, please contact or phone 6551 8002.

Page last reviewed 21 July 2021
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