There are 4 types of waste water control or septic systems available in the Adelaide Plains Council area - the conventional septic system, Aerobic systems, the Mallala sewer scheme and the Middle Beach STED scheme. There are also a range of other systems available, such as composting toilets, reed beds which may be assessed by Council providing they have been given system approval by the Department of Health.


Septic Tank Systems

A conventional septic system may be either all purpose or a water closet (WC) only, regardless of which, both systems function in the same manner. The system consists of two components, the septic tank and a soil absorption field or soakage trench. The tank will be installed in the ground with an access shaft over the lid opening to allow access for the tank to be pumped out (every 4 years). The trench system is also under ground and will only be visible via a breather pipe or vent pipe.

The system takes all household wastewater, the solids settle at the bottom of the tank while the fats float to the surface of the tank. The liquid portion (effluent) gradually moves into the trench (leaving the solids and fats behind) where it then soaks into the soil. If the tank is not pumped regularly to remove the solids then these solids will also begin to migrate through to the soakage trench. This is the main reason that these systems breakdown. The solids and fats can not be absorbed into the soil but rather clog the soil, which in turn prevents the effluent from soaking away. The only way the effluent can then escape is to break through to surface level, where it becomes a health hazard.


Mallala Sewer Scheme

This scheme is operational within the township of Mallala only and involves houses to be connected direct to a common sewer drain without the need for a septic tank All waste water is transported to a treated facility, the treated water will be used for irrigation purposes.


Middle Beach STES

The community of Middle Beach is connected to a septic tank efficient disposal system where the septic tank removes sludge and scum and is then pumped to a treatment plant with the treated waste water used as irrigation water.

Aerobic Wastewater Treatment Systems

Aerobic wastewater treatment systems may consist of a one or two tank system. They include a primary treatment component and a secondary treatment component where the wastewater is aerated and clarified before being stored in a pump chamber. The pump chamber is where disinfection occurs prior to the reclaimed water being discharged to the designated irrigation area. These systems require quarterly maintenance servicing by an accredited agent to ensure the reclaimed effluent complies with the discharge criteria stipulated by the DOH (Department of Health - SA). There is a cost associated with the service and a report must be submitted to Council by the agent to comply with the conditions of approval.


Which System?

The above systems are all acceptable in the Adelaide Plains Council, provided they comply with the Standard for the Construction, Installation and Operation of Septic Tanks in South Australia. The standard requires that each site be assessed for suitability of any chosen system.

Please note that this information is only intended as a guide and does not allow for all possible scenarios.

For further information please contact the Environmental Health section on Tel: 08 8527 0200


Site and Soil Report Requirements

The wastewater engineer must provide a site and soil suitability report to the relevant authority.
The report must include, but not be limited to:

  •  Details of the investigations carried out
  •  Site plan clearly showing:
    •  Soil sampling locations
    •  Allotment dimensions
    •  Location and dimensions of the proposed land application system
    •  Existing and proposed buildings and structures e.g. retaining walls
    •  Details of earthworks proposed as part of the site development
  • Type of proposed system to be installed
  • Information about the soil types encountered at the sampling locations in the area of the proposed land      application system
  • Nominated effluent percolation rate (EPR), design loading rate (DLR) or design irrigation rate (DIR) as applicable 1
  • Design of the land application system including soil horizon at which the base of the land application systemis to be founded
  • Assessment of site suitability for long term effluent disposal/reuse 
  • A summary of site characteristics as described in On-Site Wastewater Systems Code
  • Supporting information with respect to climate characteristics including rainfall and evaporation which may affect the performance of the wastewater system
  • Comments regarding features on adjoining allotments which may affect or be affected by the proposed wastewater system
  • Any required surface water diversion
  • Any limitations of the proposed system
  • Any other requirements of the relevant authority.

* Locations with highly permeable soils have an increased risk of effluent /recycled water polluting surface and/or ground waters.
Careful consideration is necessary to mitigate the risk, and additional design and/or construction may be necessary. Soils
demonstrating a percolation rate of greater than 150 mm /hour or category 1 and 2 soils as determined by AS/NZS 1547
(see chapter 9) require additional consideration. The site and soil assessment report shall include statements, supporting
information and detailed strategies which will be used to minimise the risk of effluent/recycled water from the on-site
wastewater system polluting ground and/or surface waters.


Application Forms and Fees

The construction, installation or alteration of an on-site watewater syatem requires approval under the provisions of the South Australian Public Health (Watewater) Regulations 2013.

No work in relation to the construction, installation or alteration of a waste control system can occur until the approval of the relevant authority has been granted. The installation or alteration of a waste control system is primarily a role of the local Council.

The Adelaide Plains Council is responsible for the approval and inspection of all installations and alterations in the district. This requires all applicants to advise Council of any work that they are undertaking in the area. Plumbing work can only be carried out by licensed operators and this includes owner/builders. 

Application forms can be downloaded as a PDF document from the list below:

Wastewater System Application Form (Septic tank)

Contact Us

2a Wasleys Road

PO Box 18

Mallala SA 5502