Septic tanks

The majority of areas within the Town of Kwinana urban area are connected to the sewer, however the rural area requires on-site effluent disposal systems to be installed.

Generally these systems comprise of two septic tanks and two leach drains or four soakwells.

The type of effluent disposal system required will depend on:

• the size of your house
• soil type on the property
• depth to the water table and;
• the environmental sensitivity of the area

In some areas, aerobic treatment units and nutrient retentive systems are also necessary to ensure that phosphorous does not impact on natural water bodies.

What to consider when deciding on a location for a septic tank:

• septic tanks and leach drains must be a minimum of 1.2m away from trafficable areas
• septic tanks must be a minimum of 1.2m from any structure
• leach drains must be a minimum of 1.8m from any structure and 1.2m from trafficable areas
• the bottom of a leach drain must be a minimum of 1.2 m above the highest known ground water level
• leach drains must be at least 30m away from any water course or bores used for potable water and at least 15m away from all other water courses or bores.

Application process

Before installing an effluent disposal system on your property you need to complete an Application to Construct or Install an Apparatus for the Treatment of Sewage.

This form with two sets of detailed plans (1:100 or 1:200 scale only) of the proposed system must be forwarded to the Town's Environmental Health Services Section along with the appropriate fee.

Decommissioning of septic tanks

Information handout