In this guide:
What is a Granny Flat?
In NSW planning terms, a granny flat is called a secondary dwelling. It's a self-contained dwelling on the same lot as your main house, with its own kitchen, bathroom, and living areas.
Secondary dwellings can be:
- Detached – A separate building in your backyard
- Attached – Connected to the main house
- Within the main house – A converted garage or basement
Despite the name "granny flat," there's no requirement for the occupant to be a family member. You can rent it to anyone.
The Rules in NSW
Secondary dwellings in NSW are governed by the State Environmental Planning Policy (Housing) 2021, which sets out state-wide rules.
Key requirements:
| Maximum floor area | 60sqm |
| Minimum lot size | 450sqm |
| Number allowed | One per lot |
| Zones permitted | R1, R2, R3, R4, RU5 and some others |
| Separate subdivision | Not permitted (must stay on same title) |
💡 The 60sqm limit
The 60sqm is internal floor area. It doesn't include garages, verandahs, or porches (unless enclosed). A well-designed 60sqm granny flat can include 1-2 bedrooms, bathroom, kitchen, and living area.
What to Check on Your Property
Before you start planning, verify these things about your property:
1. Lot size
Your lot needs to be at least 450sqm. Check your Deposited Plan or certificate of title for the exact area.
2. Zoning
Secondary dwellings are permitted in most residential zones. Check your LEP zoning. Rural zones have different rules.
3. Existing dwellings
You can only have one secondary dwelling per lot. If you already have one (or a dual occupancy), you can't add another.
4. Easements and covenants
Check your 88B instrument for:
- Drainage easements you can't build over
- Covenants restricting additional dwellings
- Building envelopes or setback requirements
5. Site constraints
Check your Section 10.7 certificate for:
- Flood affectation
- Bushfire prone land
- Heritage listing or conservation area
- Contamination
These constraints don't necessarily prevent a granny flat, but they may affect your approval pathway or require additional design considerations.
Approval Pathways
There are two ways to get approval for a granny flat in NSW:
Complying Development Certificate (CDC)
The fast-track option. If your granny flat meets all the standards in the Housing SEPP and Codes SEPP exactly, you can get a CDC from council or a private certifier.
Typical timeframe: 10-20 days
Cost: $1,500-3,000 for certification
You can't use CDC if:
- Property is heritage listed or in a Heritage Conservation Area
- Land is flood prone (above certain thresholds)
- Land is bushfire prone BAL-40 or BAL-FZ
- The design doesn't meet every standard exactly
Development Application (DA)
If you can't use CDC, you'll need a DA to council. This is also the pathway if you want to vary any standards.
Typical timeframe: 40-90 days
Cost: $2,000-5,000 including application fees and consultant reports
DAs allow more flexibility but take longer and require neighbour notification.
Typical Costs
Granny flat costs vary significantly based on size, finishes, and site conditions. Here's a rough guide:
| Component | Budget Range | Mid-Range |
|---|---|---|
| Design & approvals | $5,000-10,000 | $8,000-15,000 |
| Site works | $5,000-15,000 | $10,000-25,000 |
| Construction (60sqm) | $80,000-120,000 | $120,000-180,000 |
| Services connection | $5,000-15,000 | $10,000-20,000 |
| Total | $95,000-160,000 | $150,000-240,000 |
⚠️ Get proper quotes
These are indicative figures only. Costs vary significantly by location, site conditions, and finish level. Always get detailed quotes from licensed builders before committing.
Renting Out Your Granny Flat
Yes, you can rent out your granny flat to anyone. There's no requirement for the tenant to be a family member.
Rental considerations:
- Separate metering – Consider installing separate electricity and water meters for fair billing
- Privacy – Design for good separation between dwellings (fencing, screening, separate entrances)
- Parking – Council may require an additional parking space
- Access – Tenants typically need independent access without going through your property
Rental income potential
Granny flat rents in Sydney typically range from $350-550/week depending on location and quality. Regional areas are lower. A well-located granny flat can generate $18,000-28,000 per year in rental income.
Next Steps
- Check your property – Verify lot size, zoning, and any constraints
- Get a site assessment – Identify the best location on your lot
- Design – Work with a designer or use a standard design from a granny flat company
- Approvals – Lodge CDC or DA as appropriate
- Build – Engage a licensed builder