Only approved wastewater systems can be used in WA. Premises owners who install an unapproved system contravene the Health (Treatment of Sewage and Disposal of Effluent and Liquid Waste) Regulations 1974 (external site).
The Department of Health (DoH) requires certification for all onsite wastewater treatment systems against the relevant Australian Standard as detailed in the table below:
| Type of Onsite Wastewater System |
Capacity (L/day) |
Standard |
| Precast concrete septic tanks |
6000 |
AS 1546.1 or *DoH approval |
| Glass fibre-reinforced plastic or plastic septic tanks |
6000 |
AS 1546.1 |
| Waterless composting toilets |
N/A |
AS 1546.2 |
| Secondary treatment systems |
5000 |
AS 1546.3:2017 |
| Greywater treatment systems |
1000 |
AS 1546.4 |
*DoH approval as per Appendix 1 of Code of Practice for Product Approval of Onsite Wastewater Systems (2013)
All onsite wastewater treatment systems with the hydraulic capacities below the volumes in the table must be approved by the DoH. The approved onsite wastewater treatment systems are listed below. On how to obtain certification of wastewater system against the relevant Australian Standard please refer here.
Onsite wastewater treatment systems with capacities exceeding the volumes presented in the table require engineering certification to accompany each application to install the system. It is recommended to submit an engineering certification for each system model at once so that the documentation is on the DoH records for any future applications.
The DoH will approve and publish onsite wastewater treatment systems with capacities above volumes listed on the table that have StandardMark certification to the relevant Australian Standard.
Approved wastewater systems include:
Last reviewed: 02-08-2021
Produced by
Environmental Health Directorate