The Ultimate Guide to Granny Flat Regulations in Australia (2025 Update)

A secondary dwelling, or granny flat, is a powerful way to unlock the potential of your property. Whether for family, rental income, or a private retreat, the journey begins with a clear understanding of the rules. However, navigating the web of state and local council regulations can be the most challenging part of the project.

This comprehensive guide breaks down the granny flat regulations for every Australian state, giving you the in-depth knowledge needed to plan effectively. We'll cover everything from size limits to rental rules, empowering you to move forward with confidence—especially if you're considering the flexibility and control of an owner-builder path.

New South Wales

NSW offers one of Australia's most streamlined approval pathways, known as Complying Development (CDC), which can bypass a full Development Application (DA) if your project meets all criteria.

• Maximum Size: A firm 60m² gross floor area (GFA).
• Minimum Lot Size: Your property must be at least 450m².
• Key Setbacks: Typically requires a 3m rear setback and 0.9m side setbacks, though this can vary based on lot size and building height.
• Occupancy & Rental: Granny flats can be rented out to any party, making them an excellent investment vehicle in NSW.
• Approval Pathway: If you meet all criteria, you can get approval through a private certifier via the CDC pathway in as little as a few weeks. Otherwise, a DA through your local council is required.

Victoria

Following significant reforms, Victoria has made it much easier to build a "small second home," removing the old restrictions that limited occupancy to a dependent person.

• Maximum Size: 60m² GFA.
• Minimum Lot Size: No minimum lot size is specified, making it accessible for many properties.
• Key Setbacks: Must adhere to the same setback requirements as a standard home under the local council's planning scheme.
• Occupancy & Rental: The small second home can be occupied by family or rented out. It cannot be subdivided or sold separately from the main dwelling.
• Approval Pathway: A planning permit is no longer required on most residential lots. However, a building permit is always required to ensure the structure meets safety and building codes.

Queensland

Queensland's regulations are heavily influenced by individual local councils, meaning the rules can differ significantly from Brisbane to the Gold Coast or a regional area.

• Maximum Size: Varies by council. For example, Brisbane City Council generally allows up to 80m². The proposed state code suggests 80m² for lots under 1,000m² and 100m² for larger lots, but this is not yet uniformly adopted.
• Minimum Lot Size: Also council-dependent. Some urban areas require at least 450m²-600m².
• Key Setbacks: Determined by the local planning scheme.
• Occupancy & Rental: As of recent changes, granny flats can generally be rented to anyone, not just family members.
• Approval Pathway: Typically requires a Development Application (DA) through the local council, which assesses the project against its specific planning scheme.

Western Australia

In WA, granny flats are referred to as "ancillary dwellings" and are governed by the state's Residential Design Codes (R-Codes).

• Maximum Size: Generally limited to 70m² GFA.
• Minimum Lot Size: No specific minimum, but the lot must be large enough to accommodate the ancillary dwelling while meeting all other R-Code requirements (e.g., open space, parking).
• Key Setbacks: Governed by the R-Codes, which vary based on the density coding of your area.
• Occupancy & Rental: Can be rented out to non-family members.
• Approval Pathway: Requires a building permit from the local council. A planning permit (DA) may also be needed if the design doesn't fully comply with the R-Codes.

South Australia

South Australia's rules for "ancillary accommodation" are becoming more flexible, but are still largely dictated by local council Development Plans.

• Maximum Size: Typically around 60m² or 70% of the main dwelling's footprint, whichever is less.
• Minimum Lot Size: No state-wide minimum, but determined by council development plans.
• Key Setbacks: Must comply with local council requirements.
• Occupancy & Rental: Historically limited to dependent family members in many areas, but reforms are making it easier to rent them out on the open market. Check with your council.
• Approval Pathway: Requires lodging an application for development consent through the PlanSA portal or directly with the local council.

Tasmania

Tasmania defines granny flats as "secondary residences," with clear and consistent rules across the state under the Tasmanian Planning Scheme.

• Maximum Size: 60m² or 30% of the main home's GFA, whichever is less.
• Minimum Lot Size: No specified minimum.
• Key Setbacks: Must comply with the same setback rules as the primary home.
• Occupancy & Rental: Generally intended for family members. Renting to the public may be restricted, and the dwelling cannot be separately metered.
• Approval Pathway: Requires a Development Application with the local council.

Australian Capital Territory

The ACT has some of the most progressive and generous rules for "secondary residences" in the country.

• Maximum Size: A generous 90m² GFA.
• Minimum Lot Size: The previous 500m² minimum has been removed, allowing secondary residences on blocks of any size.
• Key Setbacks: Must comply with the Territory Plan's setback requirements.
• Occupancy & Rental: Can be rented out without restriction.
• Approval Pathway: Requires a Development Application (DA) to be lodged with the Environment, Planning and Sustainable Development Directorate (EPSDD).

Northern Territory

The Northern Territory Planning Scheme 2020 uses the term dwelling‑independent for a granny flat or ancillary dwelling.

• Maximum Size: 80m² in rural zones and 75m² in other zones.
• Key Setbacks: Must comply with standard development requirements like building setbacks and height controls.
• Occupancy & Rental: Can be rented out.
• Approval Pathway: Building and planning approvals are generally required from the Development Consent Authority.

Beyond the Basics: Other Factors to Consider

Beyond the core rules, remember to investigate these critical factors for your property:

• Utilities & Connections: How will you connect water, sewer, and electricity? Some states require these services to be shared with the main house.
• Easements & Covenants: Check your property title for any easements (e.g., for sewer lines) or covenants that might restrict where you can build.
• Bushfire & Flood Zones: If your property is in a designated bushfire (BAL) or flood-prone area, you will face additional, non-negotiable construction requirements.

Your Path to Building

Once you've confirmed your local requirements, the next step is to consider your building strategy. Engaging a turnkey builder offers a hands-off approach, while acting as an owner-builder provides ultimate control and can be a highly rewarding way to manage your project. Check out our detailed guide on becoming an owner-builder to see if this path suits you This path is particularly effective when paired with our comprehensive design and supply package, which streamlines material procurement and ensures quality from the start.