Granny flats · Sydney growth areas
Granny flats in Oran Park, Marsden Park, Box Hill and the growth areas
The new suburbs of Sydney's South West and North West growth areas are not zoned by a council plan but by state precinct plans — and those plans allow a bigger granny flat than most councils: up to 75 m² or 110 m² instead of 60 m². What your block needs, read from the precinct plans' own text.
Size and lot rules by area
| Council and suburbs | Largest granny flat | Smallest lot |
|---|---|---|
| Camden Oran Park, Gregory Hills, Gledswood Hills, Catherine Field, Leppington (part) | 75 m² or 30% of both homes | 450 m² in R1 and R2; in R3 the lot minimum for the house |
| Liverpool Austral, Leppington (part), Edmondson Park | 75 m² or 30% of both homes | 450 m² in R2 where the density map shows 10–20 homes a hectare; otherwise the lot minimum for the house |
| Campbelltown Denham Court (East Leppington) | 110 m² or 30% of both homes | 450 m² in R2; in R3 the lot minimum for the house |
| Blacktown Marsden Park, Schofields, Tallawong, Riverstone, Melonba, Grantham Farm, Nirimba Fields | 110 m² or 30% of the house (60 m² in Riverstone East Stage 3) | 450 m² in R2; in R3 the lot minimum for the house |
| The Hills Box Hill, North Kellyville, Rouse Hill (part) | 110 m² or 30% of the house (60 m² or 20% in North Kellyville) | 450 m² in R2 and R3 |
“Or 30%” means whichever is greater, so on a large house the granny flat can be bigger again. Parking is not counted.
The fast route: a CDC
On a lot of at least 450 m² and 12 m wide, a private certifier can approve a granny flat as complying development under the state Housing SEPP — usually in a few weeks. That route caps the granny flat at 60 m². To use the larger 75 m² or 110 m² allowance, lodge a DA with the council, which applies the precinct plan's figure.
Smaller lots
Many growth-area lots are 300 to 400 m². In R2 the precinct plans set 450 m² for a granny flat, so most of those cannot take one. In R3 (medium density) the test is the lot minimum for the house itself, so a smaller R3 lot can still carry a granny flat by DA — the zone of your lot decides, and the address check reads it.
What catches owners out here
- Estate covenants — many new estates have a developer's restriction on title (a section 88B instrument), and some limit a second dwelling for the first years. It is on the title, not the planning maps; check it before you design.
- Bushfire — the growth-area edges are often bushfire-prone; that does not stop a granny flat, but it needs a bushfire (BAL) report and can rule out the CDC.
- Easements and sewer — order the section 10.7 certificate and the sewer diagram before you design.
Where the figures come from
- Camden: Precincts—Western Parkland City SEPP: Oran Park and Turner Road, Camden Growth Centres
- Liverpool: Precincts—Western Parkland City SEPP: Liverpool Growth Centres, Leppington Town Centre
- Campbelltown: Precincts—Western Parkland City SEPP: Campbelltown Growth Centres
- Blacktown: Precincts—Central River City SEPP: Blacktown Growth Centres, Schofields, Alex Avenue and Riverstone, Area 20
- The Hills: Precincts—Central River City SEPP: The Hills Growth Centre Precincts, North Kellyville
Each precinct plan's clause 5.4(9) sets the size and its clause 4.1 the lot minimum for a secondary dwelling. Read on legislation.nsw.gov.au, October 2026. Dual occupancies and other housing in these precincts are not yet in the address check.
Enter the address — lot, frontage, zone and the precinct plan's size rule, in about ten seconds.