Septic tank permits
A permit is required before commencing Alterations or Installation of any Onsite Wastewater Management Systems (OWMS), commonly referred to as Wastewater (septic) Systems.
When Do I need to apply for a permit to install/alter?
Under the Environment Protection Act 2017, the Building Regulations 2018 and the Shire’s Onsite Wastewater Management Plan (OWMP), obtaining a permit from Council is required for any system with a design or actual flow rate of ≤ 5,000 Litres per day within un-sewered areas of the Mornington Peninsula.
If the OWMS will treat more than 5,000 Litres per day, please contact the Environment Protection Authority.
To find out if sewer is available to your property, please contact South East Water.
A permit to install/alter must be applied for in the following scenarios:
- Renovations & Extensions (Building Act 'Report and Consent'): Under Regulation 132 of the Building Regulations, a building surveyor cannot issue a building permit for works involving the installation or alteration of a wastewater system until they receive the "report and consent" of the Council. A report and consent is usually in the form of a Permit to Install/Alter. This ensures the proposed building works are technically compatible with the site's wastewater capacity.
- Building Over a System: You are required to obtain Council consent if you plan to construct a building, deck, or structure over any part of an existing treatment system. A permit will not be granted for building on a land application area. This is a critical safety check to prevent damage to the infrastructure or restricted access for maintenance.
- Adding Habitable Rooms: A ‘Report and Consent’ A20 permit is mandatory for any potential increase in wastewater generation resulting from the addition of habitable rooms. When calculating daily loads, Council counts any self-contained room with an area ≥ 7.5m² and no other clearly defined function (e.g., a study, library, or sunroom) as a bedroom, unless evidence is provided to the contrary.
- Plumbing Fixtures: A ‘Report and Consent’ A20 permit is required for the addition of fixtures that results in a potential increase in wastewater generation. If internal plumbing is being added, altered, or re-located but no additional wastewater will be generated, you must still apply for a ‘Minor Alteration’ A20 permit.
- Replacing a Failing System: If your system is failing or discharging effluent beyond your allotment boundaries, you must apply for a permit to install/alter your system to ensure it meets current Standards and EPA Guidelines.
- Physical System Alterations: A permit is required for physical changes to the system's design or construction, such as relocating the treatment tank or shifting the Effluent Dispersal System (EDS) to a different location on the property.
- Subdividing Your Land: If you subdivide a developed lot, any existing system that becomes non-compliant due to new boundary setbacks must be upgraded to meet current standards under a new permit.
Important Reminders:
- Sewer Availability: A permit to install or alter an OWMS will not be issued if reticulated sewerage is available to the property; connection to the sewer is mandatory in these areas.
- Maintenance vs. Alteration: General maintenance (such as desludging or minor repairs) does not require a permit, though you are legally required to keep maintenance records for five years and provide them to council upon request.
- The Certificate to Use: Once works are finished, you cannot legally operate the system until Council has conducted a final inspection and issued a Certificate to Use (CTU).
- Definition of "Alter": Under the Regulations, an alteration includes any change to the operation of the system or the premises which may increase the hydraulic flow or organic load, even if the treatment tank itself is not physically moved.
General Environmental Duty (GED): Regardless of whether a specific work triggers a permit, all owners have a legal obligation to proactively manage their system to prevent any risk of harm to human health or the environment from wastewater.
How to apply for a Permit
Please allow up to 42 working days for the processing of a permit application to Alter or Install a Wastewater (septic) Tank System.
The current fees for an application to Install or Alter a wastewater (septic) system are in the Shire's Environmental Health Fee Schedule Effective 1 July 2025(PDF, 134KB).
These fees are statutory and set by the EPA - $798 for new installation and $608 for minor alterations. The base fee for a new application is 8.2 hours of officer time. A fee of $92 will apply for each additional hour of processing time after 8.2 hours.
Application to Install a Wastewater (septic) system
Apply online below to Install a new Wastewater System for a proposed development.
Apply Online to Install
Application to Alter a Wastewater (septic) system
Apply online below to upgrade an existing Wastewater system or connect to an existing Wastewater system. Alterations can include addition of a macerator pump station, additional tanks or upgraded/extended disposal system.
Apply Online to Alter
Request a Final Inspection
The Permit to Install does not allow the Wastewater (Septic) Tank System to be used. After the installation has been completed, a final inspection needs to be conducted by an Environmental Health Officer prior to issuing the Permit to Use. Once the Permit to Use has been issued, the Wastewater tank can be used. To organise a final inspection of a Wastewater Tank, complete the form below:
Request a Final Inspection Online
Illegal use of a Wastewater Tank System (i.e. without a Council permit) may result in enforcement action. It is also a requirement that a Permit to Use a Wastewater Tank System must be issued prior to a Building Surveyor issuing a Certificate of Occupancy or Certificate of Final Inspection, as governed by the Building Act, 1993.
Design and Installation Guidelines
The installation or alteration of an Onsite Wastewater Management (Septic) System must comply with relevant legislation and guidance.
The Shires OWMS Design and Installation Guidelines and Wastewater Management Policy provide guidance on the Installation and management of an OWMS.
Download: OWMS Design and Installation Guidelines 2026(PDF, 8MB)
Wastewater Management Policy
Further information can be found on the Environment Protection Authority Victoria website:
Commercial Premises
If the wastewater system will discharge less than 5,000 Litres per day, please contact the Environmental Health Team on 5950 1373 or email wastewater@mornpen.vic.gov.au.
If the wastewater system will discharge more than 5,000 Litres per day, please contact the Environment Protection Authority.