Onsite wastewater systems provide a method of on-site wastewater disposal that can be used to allow development of land where deep sewerage is not available.
Septic tanks
Many suburbs, including parts of Mullaloo, Burns Beach, Sorrento, Marmion, and Duncraig, initially used septic tanks. While most of these areas have transitioned to deep sewerage, some septic tanks might still exist underground. Deep sewerage remains unavailable for certain lots that are larger than 2,000sqm in Kingsley (between Lake Goollelal and Wanneroo Road), and a small section of Joondalup, necessitating the use of septic tanks or alternative onsite treatment and effluent disposal methods such as Aerobic Treatment Units (ATUs).
Requirements include:
- Regulations generally prohibit constructing buildings or structures within 1.2m of septic tanks or ATUs or 1.8m from effluent soak wells and leach drains, unless otherwise approved.
- Areas above septic tank systems should not be paved unless access to the system is still available without requiring the removal of paving. Consequently, properties with septic systems face limitations on constructing pools, retaining walls, gazebos, or granny flats. However, when deep sewerage becomes accessible, property owners can connect to the sewer and decommission their septic tanks and wastewater systems.
Greywater systems
Greywater is used to describe the wastewater generated from bathrooms, laundries and kitchens, but does not include toilet wastewater. The opportunity exists for greywater to be re-used to irrigate gardens and, considering the dry environment in many parts of Western Australia, it is important that water is used efficiently and conserved whenever possible. Only approved greywater systems can legally be installed in WA.
For more information visit the Department of Health website.
Guidelines for installation and decommissioning of wastewater systems
Useful resources
For more information on waste water systems visit the Department of Health website.
The WA Department of Health Code of Practice for the Reuse of Greywater (PDF) outlines acceptable greywater re-use practices to ensure the conservation of ground and surface supplies and the protection of health standards. The installation and operation of all greywater systems must comply with the code.