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A second home on the block, a guide by Dotto

Sheet 2 · New South Wales

Secondary dwellings in New South Wales

In NSW a granny flat is a “secondary dwelling”: a self-contained dwelling within, attached to, or separate from another dwelling on the same site. It may be approved with development consent from council, or as complying development if it meets the standards in the State Environmental Planning Policy (Housing) 2021, the Housing SEPP.

General information, not legal advice. The NSW Department of Planning’s secondary dwellings page and your council’s local environmental plan are the places to check for your own lot.

Three places a NSW secondary dwelling can sit Three small lots side by side. In the first, the granny flat is a coloured room inside the grey main house. In the second, it is joined to the side of the house. In the third, it stands on its own at the back of the lot.
Drawn for this guide. Left to right: within the main house, attached to it, and separate from it. The department’s definition covers all three.

Where a granny flat may go

The department says secondary dwellings are permitted in the residential zones R1, R2, R3, R4 and R5, and that a council’s local environmental plan can allow them in other zones as well. So the zone is the first thing to find out.

Rural zones have a rule of their own. The Housing SEPP added an optional clause 5.5 to some local environmental plans, with controls on the maximum floor area and on the distance between the main house and the secondary dwelling in a rural zone. Each inclusion responds to a decision of that council, and the department’s advice is to check your local environmental plan to see what applies.

One main house, one granny flat

Two limits hold whichever route is taken. A lot on which a secondary dwelling is built cannot be subdivided, and the development can only result in one principal dwelling and one secondary dwelling on the site. Under these rules, a granny flat shares the lot rather than becoming a lot of its own.

The department also notes that the planning provisions moved from the State Environmental Planning Policy (Affordable Rental Housing) 2009 to the Housing SEPP. Older guides, and the NSW Planning Portal’s own granny flat page, still name the earlier policy.

Two routes to approval

The two approval routes for a NSW secondary dwelling
RouteWho decidesWhen it is open
Development applicationYour local councilWhen a proposal does not satisfy all the requirements for complying development, the department says it may still be possible to lodge a development application with council.
Complying developmentA council or an accredited certifier, as a combined planning and construction approvalWhen the proposal meets the provisions in Schedule 1 of the Housing SEPP

The department describes complying development as a fast-track assessment. It says a complying development approval on this fast track can come through in as little as 20 days, against an average determination time for a development application of 70 days. Those are the department’s figures for complying development in general, not for granny flats alone.

What complying development asks for

The department’s pages pick out the standards people ask about most. Schedule 1 of the Housing SEPP holds the full list.

  • The lot has an area of at least 450 square metres. Below that, the development cannot be complying development, even if the granny flat is attached to the main house. The one exception is a secondary dwelling located entirely within an existing dwelling house.
  • The floor area stays within the maximum. An amendment clarified that the calculation counts the floor area of the main house and the secondary dwelling, plus any attached carport, garage, balcony, deck, patio, pergola, terrace or verandah on either one.
  • The application goes through the NSW Planning Portal. The department’s guide to complying development says all applications for complying development are lodged there.

Questions the department answers

Can the main house and the granny flat be built at the same time?

Yes. The Housing SEPP allows a new principal dwelling and a new secondary dwelling to be approved under a single complying development certificate. The granny flat has to meet the Housing SEPP and the main house the State Environmental Planning Policy (Exempt and Complying Development Codes) 2008.

Does a granny flat need its own parking space?

Under the Housing SEPP, a secondary dwelling needs no extra parking. If the plans would remove existing car parking on the lot, the department suggests checking any existing development consent and talking to your council.

Can someone live in the granny flat while the main house is rebuilt?

After a disaster, the department’s rules let people build a granny flat first and live in it while the main house goes up, where secondary dwellings are allowed. Its order of steps: approval for all the works, build the granny flat, get an occupation certificate for it, build the main house, then get a final occupation certificate for everything within 5 years of the first.

The same page says bushfire-prone land brings more requirements, and that land zoned as at risk of ember attack, or of being exposed to flames from a fire front, cannot use complying development.

What is changing

The NSW Government has proposed changes to the complying development system, including allowing variations to some development standards. The department exhibited the proposals between 14 May and 24 June 2026 and says it is reviewing the feedback before finalising the changes later this year. The department’s complying development page carries its updates on the proposals.

For who may live in a granny flat once it is built, and the tax side of renting one out, see renting out a granny flat.

Sources for this page

This guide is published by Dotto and names no builder or kit supplier. Dotto is not a builder and holds no builder’s licence or registration, and does not do or arrange building work. This is general information, not advice. Wherever an official source differs from this page, the source is right.