Installing a septic tank system


Septic tank systems, also known as wastewater management systems, are installed to treat any onsite wastewater produced on your property. These systems are only installed in areas where reticulated sewer is not available. Properties in a sewer district must connect to the reticulated sewer system provided by your water authority. To check if your property is in a sewer district please contact either Western Water or Coliban Water.

All systems should be in compliance with AS1547 On-site domestic wastewater management.

You can view a list of EPA Victoria's list of approved systems on the EPA Website.

A licensed plumber, registered by the Plumbing Industry Commission, needs to install the system, following the "Guidelines for Environmental Management: Code of Practice – Onsite Wastewater Management". These guidelines set out the roles and responsibilities of all parties, the requirements for designing and installing septic/onsite wastewater management systems, including the setback distances, and the operating and maintaining of your system.

Required permits and documentation

You must apply for a permit to install, alter or replace a septic tank system, even if a planning or building permit is not required.

When a dwelling (including studio/bed sit) is extended and there is an increase in the number of habitable rooms, there may be increased waste loads on the existing treatment system. Permission is therefore required from Council prior to the alteration.

Before you can install, replace, alter or use a system you must obtain the necessary septic permit from us. If a building permit is needed, your building surveyor will ask for a copy of these septic permits before a building permit can be issued.

You may need to have a Land Capability Assessment (LCA) of your property to decide the most suitable system to treat your wastewater. If this is required, a copy of this report will need to be included with your permit application.

You may also need a planning permit before starting any work. If a planning permit is needed, your application to install, replace or alter a septic system cannot be assessed until you have received your planning permit. Conditions on your planning permit may limit the choice, location and installation of your system.

If you require a planning permit, the following information should be considered when submitting your planning application.

When designing the septic system and effluent disposal area the following must be considered:

  • Future use of the land
  • The location must meet the minimum setback distances to boundaries, watercourses (including dams), other buildings, swimming pools, tennis courts and driveways. These distances can be found in the Environmental Protection Authority Code of Practice (891.4)
  • Keeping of livestock (cannot be on effluent disposal area)
  • Proximity of nearby trees and native vegetation.

Owners may need to include the following information with the planning application:

  • Location of existing septic system (this is so Council can be satisfied that the system will not be disturbed or built on)
  • Capacity (L) of existing septic tank and whether it is an all waste system (toilet waste and sullage) or a split system
  • Length and location of existing absorption trenches or irrigation area
  • Whether effluent is discharged offsite (into the storm water drain)
  • Other relevant information such as the location of outbuildings, dams, creeks and fences
  • Location of effluent envelop—an effluent envelope may be designated on the site as part of the planning permit or Section 173 agreement. All wastewater must be disposed of within this envelope unless consent has been given for disposal to occur in another location.
  • Land Capability Assessment (LCA) if required.

In older dwellings the system may be required to be upgraded or replaced to comply with current requirements.