NSW planning resource · $39 planning report

Can I build a granny flat in NSW?

NSW has one of Australia's most generous granny flat regimes. A 'secondary dwelling' up to 60 m² can be approved as Complying Development — a fast-track certificate, no full council DA — on a lot of 450 m² or more. Here's what's allowed, and how to check your block.

NSW homeowners weighing up a granny flat for family, rental income or a home office — who want to know whether the fast-track applies to their property before paying for design.

Check what your property allows — $39 Free NSW Spatial Viewer

The NSW fast-track: Complying Development under the Housing SEPP

In NSW a granny flat is a 'secondary dwelling' — a self-contained dwelling on the same lot as the main house. The State Environmental Planning Policy (Housing) 2021 lets you build one as Complying Development: a combined planning-and-construction certificate issued by council or a private certifier in around 20 days, without a full development application, provided you meet the development standards.

The two headline numbers: the secondary dwelling can be up to 60 m² of floor area, and the lot must be at least 450 m². Meet the standards and you skip the DA; miss them and you fall back to a merit DA, where a council can still approve a larger or differently-sited dwelling on its merits.

Up to 60 m² floor area for the fast-track (larger may be possible via DA)
Minimum lot size 450 m² for Complying Development
One secondary dwelling per lot, in addition to the principal dwelling
Permitted in the R1, R2, R3, R4 and many other residential zones
Setbacks, height and site-coverage standards apply under the code
Can be rented out — but the lot can't be subdivided to sell it separately

When you need a DA instead

A development application (rather than the fast-track) is needed if the secondary dwelling exceeds 60 m², the lot is under 450 m², or the property carries a constraint that excludes Complying Development — a heritage item or conservation area, a foreshore or environmentally sensitive area, or certain hazard-affected land (flood, bushfire). Some councils' Local Environmental Plans also set their own secondary-dwelling floor-area limit, which can be larger than 60 m² on a DA pathway.

A secondary dwelling stays on the same title as the main house. You can rent it out, but you can't subdivide to put the granny flat on its own lot under the secondary-dwelling provisions.

Check your property before you design

Whether the fast-track applies turns on your lot size, zone and any constraints (heritage, flood, bushfire). Our $39 NSW planning report reads your property's zone, lot context and overlays and gives a plain-English answer on whether a secondary dwelling is Complying Development or needs a DA.

For the detailed clause-by-clause test against the standards once you have plans, the NSW granny flat compliance check is the next step.

Real example

Worked example

A 58 m² detached secondary dwelling on a 520 m² R2 lot with no heritage or hazard constraints, meeting the setback and height standards — approvable as Complying Development, no council DA. Push it to 75 m² or put it on a 400 m² lot and it becomes a merit DA.

The statutory basis

Secondary dwellings in NSW are governed by the State Environmental Planning Policy (Housing) 2021 (Chapter 3), which sets the 60 m² floor area and permits them in residential zones. The Complying Development pathway runs through the Housing SEPP's development standards; the 450 m² minimum lot size and siting standards must be met. A Local Environmental Plan can set a different floor-area limit on the DA pathway. Always confirm the controls and constraints for your address.

SEPP (Housing) 2021 — Chapter 3

Secondary dwellings — 60 m², permitted zones

SEPP (Housing) 2021 — Complying Development

Fast-track standards (incl. 450 m² lot)

Environmental Planning and Assessment Act 1979

Complying development framework

Frequently asked questions

How big can a granny flat be in NSW?

Up to 60 m² of floor area to use the Complying Development fast-track under the Housing SEPP. Some councils allow a larger secondary dwelling on a DA pathway, so check your local LEP.

Do I need council approval for a granny flat in NSW?

Yes, but it can be fast — a granny flat that meets the standards (≤60 m², 450 m²+ lot, setbacks, no excluding constraint) can be approved as Complying Development in about 20 days without a full DA. Outside those limits you need a merit DA.

What's the minimum lot size for a granny flat in NSW?

450 m² for the Complying Development fast-track. Smaller lots may still be possible via a development application, depending on your council's controls.

Can I rent out a granny flat in NSW?

Yes — a secondary dwelling can be rented to a separate household. It stays on the same title as the main house; you can't subdivide to sell it separately under the secondary-dwelling rules.

Can I build a granny flat on a heritage or bushfire-affected property?

Heritage items/conservation areas and certain hazard-affected land are usually excluded from Complying Development, so a granny flat there generally needs a DA. The planning report flags these constraints for your address.

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