Septic tank and wastewater systems

Domestic wastewater treatment systems (septic tanks)

In areas where reticulated sewer is not available, sewage (toilet and kitchen water) and sullage (from baths, laundry, showers etc.) must be treated and contained within the boundaries of the property. This is done through the use of domestic wastewater treatment systems, commonly known as septic systems. These generally treat waste in a tank and discharge wastewater into designated effluent disposal area.  There are approximately 5,000 properties in Nillumbik Shire Council that are not connected to the sewer.

When managed and maintained correctly, these systems are a safe and effective method of treating and discharging wastewater. However, if systems fail and release untreated wastewater into local waterways or stormwater drains, they can be a threat to public health and the environment.

Septic tank systems are approved and assessed in accordance with the Environmental Protection Act 1970. Council generally does not specify which type of system must be installed, although all treatment system brands and models must be certified by an accredited conformity assessment body (CAB) as conforming to the relevant AS. This accreditation is given by JAS-ANZ (the Joint Accreditation System of Australia and New Zealand). As part of a permit application to a council, the applicant will need to include a copy of the certificate of conformity from a CAB. Valid onsite wastewater treatment system certificate holders can be accessed on the Environmental Protection Authority’s website. 

Valid onsite wastewater treatment system certificate holders | Environment Protection Authority Victoria | EPA Victoria 

Do I need a septic tank permit?

If your property is located in an area that is not serviced by sewer, an approval from Council (Environmental Health) is required for the installation or alteration to a septic system. This can take place in the planning or building permit process. Permission is required from Council prior to any installation or alteration of a septic tank system, even if a building permit or planning permit is not required.

Extensions, including studios or Dependent Person's Units may increase the waste load on an existing treatment system, therefore  we will need to ensure the septic system will be able to cope with new development/proposed extension.

If the dwelling is located in an unsewered area the planning application will be referred to the Environmental Health Unit.

Considerations 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 Environment Protection Authority Code of Practice (891.3)
  • 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: 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 stormwater drain)
  • other relevant information such as the location of outbuildings, dams, creeks and fences
  • location of effluent envelope – 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 wastewater disposal system may be required to be upgraded, or a new system installed, to comply with current requirements.

How to apply for a permit to install or alter a septic tank system

To obtain a permit to install or alter a septic tank system you need to:

  1. Check your planning permit for any conditions relating to the septic system.
  2. Discuss the types of septic tank systems available and the best type of system to meet your needs with your licensed plumber.
  3. A soil permeability test or LCA may be required. A copy of this report must be forwarded to Council with the application documents. This may have already been done as part of the planning approval process.
  4. Liaise with the licensed plumber to submit the application to Council to install or alter a septic tank system.
  5. Ensure the application form is signed by both the owner of the property, and the licensed plumber employed to undertake the works. Ensure the relevant documentation and fee accompanies the application; a site plan of the proposed system must be included with the application
  6. An environmental health officer from Council will assess the application and conduct a site inspection.
  7. Where all requirements have been met a Permit to Install a septic tank system will be issued to the nominated plumber. 

How to obtain a certificate to use a septic tank system

To obtain a permit to use a septic tank system you need to:

  1. Ensure a final inspection is conducted, once the septic system has been installed and before it has been completely backfilled, fees for additional inspections may be charged
  2. Two days’ notice is required for requesting an inspection
  3. Provide a Certificate of Compliance (Victorian Building Authority)
  4. Provide a commission report (if applicable)
  5. Provide an accurate, to scale, as-constructed site plan
  6. Provide a copy of the maintenance service agreement (if Aerated Wastewater Treatment System)

More information regarding septic tanks and their management can be found in Council's Guide to domestic wastewater treatment and disposal systems.  This document contains information on:

  • the different types of septic tank systems available;
  • what land capability assessments are and when they are required;
  • maintenance of septic tanks and effluent disposal areas;
  • setback distances from environmentally sensitive site features; and
  • the application and permit process

Contact Environmental Health on 9433 3340 or by email Health.Services@nillumbik.vic.gov.au