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What is onsite wastewater?

Sewage is wastewater that comes from toilets, bathrooms, kitchens and laundries. Most sewage goes through Victoria’s reticulated sewerage systems for treatment.

Sometimes it’s not practical, or possible, to connect to the existing sewerage system. Where this occurs, sewage is managed using a standalone on-site wastewater system such as a septic tank with a dispersal/recycling component which is designed to treat and contain waste within a property boundary.

These systems are in place across Victoria, where no sewer is available and are installed on single land title sites to treat wastewater which contains human waste. These systems can create public health and environmental issues if not maintained or correctly installed.

Onsite wastewater systems must perform effectively and be well managed to minimise risks to the environment and public health.

Who is responsible for what?

The Department of Energy, Environment and Climate Action (DEECA) and the Environment Protection Authority (EPA) are responsible for overseeing the regulatory framework that Councils and Water Corporations use to manage the risks posed by poorly performing on-site wastewater systems.

The Department is responsible for legislation for the water industry and the services it provides. We administer the Water Act 1989 and the Water Industry Act 1994 and Water Corporations’ compliance with the provisions in these Acts.

We also inform policy that supports the Environment Protection Act 2017 and subordinate legislation.

Water corporations provide sewerage, water and recycled water services to residential, commercial and industrial customers. Where on-site wastewater systems are utilised, Water corporations also work with Councils in relation to:

  • determining options for high-risk systems such as connection to a sewerage system or an alternative service
  • determining planning permit applications in special water supply catchment areas.

The EPA administers the Environment Protection Act 2017 (the Act) and Environment Protection Regulations 2021 (the Regulations) and sets out guidance for the appropriate management of on-site wastewater systems.

Councils administer the use and installation of onsite wastewater systems designed to discharge less than 5,000 litres per day of sewage in accordance with the Act, the Regulations and guidance. Councils also:

  • assess risks and identify strategies to manage these systems via the development and implementation of an onsite wastewater management plan (OWMP)
  • refer high-risk unsewered townships to Water Corporations
  • are responsible for preparing and administering planning schemes, including decisions about planning permits and referrals to Water Corporations.

VAGO Audit ‘Managing the Environmental Impacts of Domestic Wastewater’

In September 2018, the Victorian Auditor General’s Office (VAGO) released a report which made 8 recommendations to both DELWP (DEECA) and EPA.

We recommend that the Department of Environment, Land, Water and Planning (DELWP) and the Environment Protection Authority (EPA) in consultation with councils, water authorities and other key stakeholders work together to review the regulatory framework, tools, and guidance for domestic wastewater management to address issues and gaps including:

a) lack of clarity around roles and responsibilities, particularly for enforcement and power to enforce connection

b) systems approved prior to 1988 that allowed discharge of treated and/or untreated wastewater offsite or systems approved without a permit

c) overlapping, onerous and duplicative approval system

d) governance and approval processes for alternative onsite installation and servicing approaches

e) issuing ongoing permits for the use of onsite systems (Part 4).


Environment Protection Regulations 2021 in force on 1 July 2021.

Tools and guidance:

EPA developed elearning tools for Council Environmental Health Officers.

In progress

Consideration of instruments to house the saved State Environment Protection Policy (Waters) clauses.

Review of tools and guidance:

Review of the Ministerial Guidelines – Planning permit applications in open, potable water supply catchment areas.

See also #7 and #9.

We recommend that DELWP and the EPA work with councils to develop a standard risk assessment framework based on relevant Australian standards that includes comprehensive measures to assess both land capability, environmental factors and the ongoing performance of a system (Part 2).


Risk assessment guidance aligned with ISO 31000.

In progress

EPA converting the Code of Practice to a state of knowledge resource.

EPA reviewing the Land Capability Assessment framework.

We recommend that DELWP and the EPA work with councils to implement an accredited third party approval system/s for undertaking land capability assessments and inspections for the installation, use and ongoing maintenance of onsite domestic systems or introduce a mandatory requirement that a suitably qualified assessor undertakes these assessments (Part 2).


Environment Protection Regulations 2021 in force on 1 July 2021.

We recommend that DELWP and the EPA work with councils to review the model domestic wastewater management plan and ensure it is based on better practice risk assessment methodology outlined in the relevant Australian standards (Part 2).


DEECA completed a review of the model and risk assessment methodology.

DEECA issued ODWM grants program to incentivise council planning and management processes.

In progress

EPA leading the development of new model guidance for developing, reviewing, and updating on-site wastewater management plans (OWMP).

We recommend that DELWP and the EPA work with councils to evaluate and implement a better practice model for the ongoing maintenance of onsite systems including examining:

a) risk‐based maintenance models

b) use of levies to support third‐party maintenance options

c) the requirement for property owners to gain an onsite system compliance certificate prior to sale of the property (Part 3).


  • Environment Protection Regulations 2021 in force on 1 July 2021.

We recommend that DELWP and the EPA work together to improve centralised leadership arrangements to effectively oversight the performance and implementation of the regulatory framework to manage the risks posed by poorly performing onsite systems (Part 4).


The Water Quality Project Control Board has been in place since 2018 representing DEECA, EPA and Department of Health.

The group provides centralised leadership and advice on onsite wastewater management.

We recommend that DELWP and the EPA work together to oversee the development and ongoing operation of a steering committee to review issues and recommend solutions to improve the management of domestic wastewater (Part 4).


The Onsite Wastewater Steering Committee has been in place since July 2019 and meets quarterly.

We recommend that DELWP and the EPA work together to a) explore legislative opportunities to ensure properties connect to sewer at the point of sale or b) have an onsite system compliant with legislative requirements (Part 4).


a) Sewer connections options paper

b) Environment Protection Regulations 2021 in force on 1 July 2021.


  • Integrated Water Management (IWM) is a collaborative approach for Water Corporations and Councils to determine Integrated Water Management options for where sewerage cannot be provided. IWM considers how the delivery of water, wastewater and stormwater services can contribute to water security, public and environmental health and urban amenity.
  • Planning permit applications in special water supply catchment areas are in place to help responsible authorities assess planning permit applications for the use and development of land within declared special water supply catchment areas.

Case studies

We produced several case studies as part of the program to share new and innovative pilot projects.

  1. Sewer alternative in Park Orchards (Yarra Valley Water and Manningham Council).
  2. Beyond septics: Connecting more households to effective wastewater systems (North East Water).
  3. Collaboration lays the foundation for effective domestic wastewater management (Mornington Peninsula Shire and South East Water).
  4. Digitising historic records for effective domestic wastewater management (Yarra Ranges Shire Council)
  5. Penshurst rides the winds of change to test adaptive wastewater solutions (Southern Grampians Shire and Wannon Water).

Read the case studies

Page last updated: 16/04/24