On-Site Sewerage Treatment and Grey Water

An on-site sewerage facility is any system that stores, treats and disposes of household wastewater on the property. Poorly sited or maintained on-site sewerage facilities can impact public health and the environment. The owner of the facility is responsible for ensuring the system is maintained and functioning properly.

The disposal of effluent (treated sewage) may occur:

• on the property in a designated area (called a land application area)
• off the premises by a common effluent drainage system
• off the premises by collection from a holding tank by a Council-approved liquid waste carrier.

The appropriate state government agency is responsible for the assessment and approval of facilities designed to service over 20 equivalent persons.

Treatment systems for household wastewater include:

• conventional domestic sewage treatment plants (secondary treatment or better)
• aerated/aerobic sand filter system
• septic tanks (primary treatment)
• all-waste septic tank (all household wastewater)
• black water septic tank (toilet, urinal and bidet wastewater only)
• greywater septic tank (sullage wastewater only)
• composting systems
• dry vault system (toilet waste only – waterless)
• wet system ( all household wastewater – may be considered a domestic sewage treatment plant
• holding tank
• removal from the premises by collection from a holding tank by a Council-approved liquid waste carrier
• greywater treatment/diversion facility.

Although Council approves the installation of an on-site sewerage facility, the treatment system (plant or device) will require product approval from a state government department or demonstrated compliance with a manufacturing code or Australian Standard.

The designated area on a property for application of the treated effluent is referred to as a land application area and includes:

• surface irrigation (spray above ground)
• sub-surface irrigation (drippers in shallow trench)
• covered surface irrigation (drippers on natural ground covered by mulch, woodchip, etc.)
• evapotranspiration-absorption trench/bed/mound
• trench or bed (embodies the principles of evaporation, transpiration and absorption)
• elevated sand mound (specially constructed on natural ground level).

The type of land application area will depend on the level of treatment the wastewater has received prior to disposal.

You will need a Council permit before installing either:

• a greywater diversion device that diverts greywater from the bath, shower, hand basin and/or laundry to an irrigation hose

Note: Untreated greywater cannot be stored.

• a greywater treatment system that collects the greywater and treats it to a high standard for reuse as garden irrigation.

You don't need a permit for manual bucketing or connection of a flexible hose to a washing machine outlet.