A granny flat is now officially called a secondary dwelling across New South Wales, including Sydney. This is the term used in planning legislation, council documentation, and development applications throughout the state.
The informal name “granny flat” is still widely understood, but secondary dwelling is the correct legal and planning term. Knowing the difference matters when you are applying for approval, researching your property rights, or planning a build.
The Modern Term for a Granny Flat
A secondary dwelling is a self-contained residential unit located on the same lot as a principal dwelling. It has its own living space, kitchen, bathroom, and separate entry. In NSW, secondary dwellings are governed by the State Environmental Planning Policy (Housing) 2021, which sets out size limits, site coverage rules, and approval pathways.
The term applies whether the dwelling is attached to the main home, detached in the backyard, or converted from an existing structure such as a garage. The defining feature is that it sits on the same title as the primary residence and cannot be subdivided or sold separately.
Why the Terminology Changed
The shift from “granny flat” to secondary dwelling reflects a broader change in how NSW planning policy treats these structures. The older term was informal and implied a single use — housing an elderly relative. The updated terminology recognises that these dwellings serve multiple purposes: housing adult children, generating rental income, accommodating carers, or increasing housing density on existing residential lots.
NSW planning reforms over the past decade have progressively expanded the rules around secondary dwellings to address housing supply. The language changed alongside the policy to reflect that expanded role.
Which Terms Are Used in NSW and Sydney
In Sydney and across NSW, the primary official term is secondary dwelling. You will also encounter the term ancillary dwelling in some local council documents, particularly in older development control plans that have not yet been updated to align with current state policy.
In other Australian states, similar structures may be called granny flats, dependent person’s units, or ancillary accommodation. If you are dealing with a Sydney council, a certifier, or a state planning portal, secondary dwelling is the term to use in all formal correspondence and applications.
Understanding secondary dwelling approval requirements in NSW becomes the practical next step once the terminology is clear, because the name you use in your application directly affects how it is assessed.
How the New Name Affects Planning and Property Decisions
Using the correct term is not just a formality. Secondary dwelling is the classification that triggers specific planning rules, size allowances, and approval pathways under NSW legislation. If you use an incorrect or outdated term in a development application, it can cause delays or result in your application being assessed under the wrong framework.
Under the current NSW Housing SEPP, secondary dwellings in most residential zones can be approved as complying development, which is a faster, council-independent pathway. This only applies when the proposal meets the specific criteria attached to the secondary dwelling classification.
What This Means for Sydney Homeowners and Investors
For homeowners, understanding the correct term helps you navigate council websites, speak confidently with certifiers, and ensure your application is lodged correctly from the start. For property investors, the secondary dwelling classification affects how the structure is described in rental listings, lease agreements, and property valuations.
The cost of building a secondary dwelling in Sydney varies depending on size, site conditions, and whether the build follows a complying development or full development application pathway. Getting the classification right early keeps your project on the correct approval track and avoids costly rework.
Secondary Dwelling vs. Other Dwelling Types — Key Distinctions
Secondary dwellings are sometimes confused with dual occupancies and boarding houses, but these are distinct classifications with different rules. A dual occupancy involves two dwellings on one lot that can be strata-titled and sold separately. A secondary dwelling cannot be separated from the principal dwelling on title.
A studio or bedsit within the main home is not a secondary dwelling unless it meets the self-contained criteria and is formally approved as one. Unapproved structures, regardless of what they are called, carry legal and financial risk for owners and investors. Using the correct classification from the planning stage protects your investment and ensures the dwelling is insurable, leasable, and legally recognised.
Conclusion
The new name for a granny flat is secondary dwelling — the official term used in NSW planning legislation, development applications, and council assessments across Sydney.
For homeowners and investors, using the right term from the start ensures your project is assessed correctly, approved efficiently, and built to a standard that protects long-term property value.
At Sydney Home Renovation, we guide you through every stage of secondary dwelling planning and construction — from understanding approval pathways to delivering a finished build on budget and on schedule.
Frequently Asked Questions
Is a granny flat the same as a secondary dwelling?
Yes. Secondary dwelling is the official planning term in NSW. Granny flat is the informal name for the same structure. Use secondary dwelling in all council and certification documents.
What is a secondary dwelling in NSW?
A secondary dwelling is a self-contained unit on the same lot as a principal dwelling. It must have its own kitchen, bathroom, and entry, and cannot be sold separately from the main home.
Can I still call it a granny flat when applying for approval?
Informally, yes — most certifiers and councils understand the term. However, your formal application must use secondary dwelling to ensure it is assessed under the correct planning framework.
Does the new name affect how a secondary dwelling is taxed or rented?
The classification affects how the dwelling is described in lease agreements and valuations. Tax treatment depends on use and ownership structure. Consult a property accountant for advice specific to your situation.
What is the difference between a secondary dwelling and an accessory dwelling unit?
Accessory dwelling unit is a term used in the United States. In NSW and Sydney, the equivalent term is secondary dwelling. The planning rules, size limits, and approval pathways are specific to NSW legislation.