On-site wastewater management systems

On-site wastewater management systems (OWMS), including septic tank systems, are used on residential, community and businesses premises where reticulated sewer services are unavailable.

On-site wastewater treatment systems must perform effectively and be well managed to minimise risks to public health and the environment.

Permit requirements

The permit consists of a two-stage process:

  • A ‘Permit to Alter/Install’ an on-site wastewater management system. This permit must be issued before a building permit can be issued. 
  • An ‘Approval to Use’ the on-site wastewater management system.  This permit must be issued before a building Certificate of Occupancy can be issued by a building surveyor. 

Making an application for a permit – What you need to do

If you need to install or alter an onsite wastewater management system you, your plumber or builder can make application to us using an Application to install or alter an OWMS form(PDF, 107KB)

There are several documents that need to be provided to support an OWMS permit application:

  • Site plans of proposed OWMS design and location
  • Floor plans of the dwelling or premises which the system is connected to
  • Title of lot
  • Certificate of conformity for proposed treatment system
  • Land capability assessment (if required)
  • Planning permit for the development (if required)

An application must also be made to Council for changes to existing OWMS permits including:

  • Changing system design
  • Change of plumber installing the system
  • Renewing expired permits
  • Transferring the permit to new property owners

Application to amend, transfer, or renew owms

If you are unsure about the type of OWMS that you need for your property, please discuss further with your plumber or contact the Environmental Health Team on 1300 656 564.

Permit process – What Council will do

An environmental health officer (EHO) will assess the application. If the application is incomplete or supporting information is not provided, the application cannot be considered, and you will receive a request to supply further information.

Council will send out an invoice to the applicant for the relevant permit fee.

Once a complete application is received, an EHO will need to undertake a pre-inspection of the proposed site to ensure EPA requirements will be met.

If approved and once the permit fee is paid in full, we can issue you with a Permit to Install/Alter an OWMS.

You must have this permit  prior to installation of the OWMS by your plumber.

Approval to Use

When your plumber is ready to install the system, please contact the environmental health team on 1300 656 564 to book in an inspection of the system.

Depending on the system type, the EHO may need to view the system at various stages of installation. The property owner and/or the plumber should liaise with Council during all inspection stages.

It is important that a minimum of 48 hours’ notice is provided to the environmental health team to give sufficient notice to complete inspections. 

When it has been established that the OWMS meets EPA and Council requirements, we will issue an approval to Use OWMS. 

Only then can you start to use your wastewater system. Using your OWMS before an ‘Approval to Use’ has been issued can result in a penalty infringement notice.

Permit fees

Fees for OWMS permit applications are prescribed under the Environment Protection Regulations 2021. The fees for the 2023/2024 financial year are:

Fees for OWMS permit applications
Fee type Fee unit Fee amount
Construct/install/alter OWMS(regulation 196(1)(b), (2)) 48.88 $777.20
Minor alteration to OWMS (regulation 196 (1)(a), (3)) 37.25 $592.30
Transfer a permit (regulation 197) 9.93 $157.90
Amend a permit (regulation 198) 10.38 $165.00
Renew a permit (regulation 200) 8.31 $132.10


Land capability assessments

In unsewered areas, a land capability assessment (LCA) should be undertaken for each site that requires the installation of an OWMS, unless council is satisfied that the site is low risk or sufficient information has already been gathered about the site.

Some examples of when an LCA may be required to support an application include:

  • Small lot size (under 4000m2)
  • Soils with very low permeability
  • Groundwater quality at risk
  • Development use (i.e., high loading rate due to commercial/industrial activities)
  • Susceptible ecological areas or water bodies nearby
  • Lot characteristics such as slope, location of drains/easements/water courses etc

It may be one factor alone that triggers the need for an LCA or a combination of factors.

Individual landowners or developers (not EPA or Councils) are responsible for engaging a suitably qualified and experienced professional to undertake a LCA for unsewered developments or subdivisions. The Victorian Land Capability Assessment Framework, 2014 provides further guidance.

If you are unsure if an LCA is required to support an OWMS application, please contact the Environmental Health Team on 1300 656 564 or moyne@moyne.vic.gov.au .

Operating and maintaining an OWMS

OWMS have the potential for major environmental and human health risks. Poorly installed or maintained systems, particularly old legacy systems, can create serious hazards. These might include polluted drinking water, contaminated land and water bodies, and offensive odours.

Owners and occupiers have a responsibility to minimise these risks, so far as reasonably practicable.

Read more about OWMS and wastewater on the EPA website .

To keep the system working well

use biodegradable soaps and low-phosphorus, low sodium detergents
arrange for regular servicing of treatment plants
keep livestock and vehicles off the system
divert stormwater runoff away from trenches or irrigation areas
don’t use powerful bleaches, whiteners, nappy soakers, spot removers and disinfectants
don’t put chemicals or paint down the drain
don’t put pads, tampons or nappies into the system
don’t build over the system (driveways, sheds, units etc.)

To reduce sludge building up in the tank

scrape all dishes to remove fats, grease and food scraps before washing
keep food waste out of the system
pump out the tank at least once every three years

Avoid overloading the system

space out water use as evenly as possible
wash clothes only when there is a full load
install water conservation fittings
take showers instead of baths

avoid doing all the washing on one day
avoid using the washing machine and dishwasher at the same time

Servicing of Aerated Wastewater Treatment Systems (AWTS)

An AWTS is a purpose-built mechanical treatment system used to treat wastewater to a secondary quality. Wastewater flows through a series of treatment and disinfectant processes where it is usually dispersed via sub-surface irrigation. Compared to a standard septic tank, an AWTS requires quarterly servicing by a suitably qualified technician.

As an owner of an AWTS you should

Have it serviced every three months or as required by EPA certificate of approval to maximise the performance of your system. This service needs to be undertaken by a competently trained person or company and they should be contracted to undertake the task.
Have it de-sludged once every 3-5 years.
Ensure it is accessible for servicing and other works. The system should be free of overgrown vegetation, rubbish and any other obstructions.
Have it repaired quickly if the alarm goes off. The alarm indicates that one of the mechanical devices that operate within the system has failed or malfunctioned.

A copy of the maintenance report is to be submitted to the Council after each service.  Routinely check the irrigation filter (between the irrigation field and the AWTS) and clean it if needed. Please be careful when cleaning the filter because you will be dealing with effluent that could contain pathogens that can affect your health.

Routinely check that the irrigation system is working adequately. Some common signs that the irrigation field is struggling or failing include water ponding, the ground being heavily saturated, or significant vegetation die off.

There are several service agents that operate within or regularly visit the southwest region to service ATWS. If unsure, please contact the company or plumber that provided or installed your system.

Dealing with OWMS failures

It is essential to be vigilant about potential OWMS failures. This means paying attention to key warning signs and taking steps to address the issues, even if this might be contained to your property.

Warning signs of failure may include:

  • the absorption field becoming wet with wastewater pooling on the surface
  • wastewater runoff from the disposal area
  • a smell of effluent near or from the system
  • Shower, basin or toilets draining slowly

If you suspect your system may be failing, please contact a licensed plumber to inspect the system.

The regulations also require landowners and occupiers to tell their council if their OWMS shows any signs of failure. You will need to explain to a council officer what has or is being done to fix the problem.

If others detect and report issues to council – such as offensive smells - and the owner or occupier has not reported it, a penalty may apply to the owner or occupier.

Please contact the Environmental Health Team on 1300 656 564 or moyne@moyne.vic.gov.au for further information.