Requirements when sewer is not available

Where sewer is not available an effluent disposal system must be installed. The Department of Health is responsible for approving the types of onsite effluent disposal systems allowed in Western Australia.

The Shire's Health Services can generally provide approval for the installation of approved types of Effluent Treatment and Disposal Systems for a specific lot, subject to certain conditions.

The following types of effluent disposal systems have been approved by the WA Health Department and can be installed in the Shire of Mundaring.

Approved types of effluent disposal systems

Conventional septic systems

These systems incorporate two septic tanks (this may be a single, baffled tank if using plastic) and two leach drains. The septic tanks digest all solid and liquid wastes to a primary standard which is discharged into the ground via leach drains.

Aerobic treatment units

These units incorporate aeration systems to aid in the breakdown of waste to a secondary level. The effluent is further treated and disposed of either by surface irrigation, sub-soil dripper or leach drain system. Aerobic treatment units do tend to lend themselves to environmentally or space constrained lots owing to the increased flexibility offered by these systems

Greywater systems

These units divert off greywater (typically bathroom and laundry) waste from the house and treats and disperses it separately from either the main effluent disposal system, or from entering the sewer network. 

More information and contact

For more information on types of effluent disposal systems, please contact the Shire’s Health Services on 9290 6742 or email