Can I build a granny flat on my property in NSW?
Five questions determine whether your property qualifies for a secondary dwelling under the SEPP Housing 2021 complying development pathway. Most properties in residential zones pass. Here is how to check yours.
Granny flat eligibility — key gates (SEPP Housing 2021)
Is your lot zoned R1, R2, R3, or RU5?
Check your zoning at planning.nsw.gov.au or via PlotDetect
Is your lot at least 450 m²?
Some councils accept smaller lots via DA, but CDC requires 450 m²
Is the property free of heritage listing or heritage conservation area?
Both individual heritage items and HCAs are excluded under Cl 37(1)(d)
Is the property outside a flood planning area?
Flood planning areas are mapped by council, not always on planning certificates
Is the property free of biodiversity / acid sulfate constraints?
Key requirements at a glance
Under State Environmental Planning Policy (Housing) 2021, a secondary dwelling (granny flat) can be approved as complying development if the property meets these minimum standards:
Minimum lot size
450 m²
Maximum floor area
60 m²
Maximum height
8.5 m (2 storeys)
Permitted zones
R1, R2, R3, RU5
Rear setback (SEPP minimum)
3 m
Side setback (SEPP minimum)
0.9 m
The 60 m² floor area cap is a hard limit under the SEPP. It applies regardless of lot size — a 2,000 m² lot still gets a maximum 60 m² granny flat under complying development. Councils cannot increase this cap.
CDC vs DA: which pathway do you need?
A Complying Development Certificate (CDC) is faster and cheaper, but only available when the property and the proposed building both meet every SEPP standard. If any standard is not met — or if the property has a constraint that excludes it from CDC — you need a Development Application (DA) through council.
CDC pathway vs DA pathway
| Complying Development (CDC) | Development Application (DA) | |
|---|---|---|
| Approval body | Private certifier | Council |
| Typical timeframe | 10–20 business days | 45–90+ days |
| Neighbour notification | Not required | Required |
| Typical cost (approval fees) | $3,000–$6,000 | $5,000–$15,000+ |
| Heritage properties | Not available | Available with heritage assessment |
| Flood-affected land | Not available | May be available with flood study |
| Floor area cap | 60 m² | 60 m² (same cap applies) |
| Design flexibility | Must meet all SEPP standards | Council can vary standards |
In practice, most standard granny flat builds on unconstrained residential lots can use the CDC pathway. The DA pathway exists for properties that are heritage-listed, flood-affected, or otherwise excluded from complying development. DA gives council discretion to approve developments that do not meet every prescriptive standard, but the process is slower and less predictable.
Common blockers that catch people out
Heritage listing or heritage conservation area
If the property is individually heritage-listed or within a heritage conservation area (HCA), complying development is not available under Cl 37(1)(d). Many inner-Sydney suburbs have extensive HCA coverage. A property does not need to be a heritage building itself — being within the HCA boundary is enough to exclude CDC. DA with a heritage impact assessment is the alternative.
Flood planning area
Properties within a flood planning area cannot use the CDC pathway for a secondary dwelling. Flood status is not always obvious from a planning certificate — after legislative changes in 2021 and 2023, some certificates show less flood information than they previously did. Check with your council or use a tool that cross-references multiple flood data sources.
Bushfire prone land
Properties on bushfire-prone land may still be eligible for CDC, but additional construction standards apply under the Planning for Bush Fire Protection guidelines. Asset protection zones and BAL ratings affect siting and construction cost. Properties rated BAL-40 or BAL-FZ face significantly higher build costs.
Strata title
If your property is on a strata lot, you cannot build a granny flat as complying development. The SEPP Housing 2021 CDC pathway requires the lot to be Torrens title. Some strata schemes may allow it via DA with owners corporation consent, but this is uncommon and complex.
Lot too small or too narrow
The 450 m² minimum is the SEPP threshold. Below this, CDC is not available. Some older inner-city lots are under 450 m² — these may still be eligible via DA if council supports secondary dwellings at merit assessment, but there is no guarantee of approval.
What the SEPP actually requires
The SEPP Housing 2021 (formerly the Affordable Rental Housing SEPP) sets out the CDC standards for secondary dwellings in Division 2, Subdivision 6. Key provisions:
- Floor area: maximum 60 m² (Cl 39(1))
- Height: maximum 8.5 m (Cl 39(2)(a))
- Rear setback: minimum 3 m (Cl 39(2)(b))
- Side setback: minimum 0.9 m (single storey) or 1.5 m (two storey)
- Landscaped area: minimum percentage of the lot must remain landscaped (varies by lot size)
- Private open space: minimum 24 m² accessible from the secondary dwelling
- Car parking: one additional space required (may be tandem or stacked with existing)
These are the SEPP minimums. Your council's Development Control Plan (DCP) may impose additional or stricter requirements on top of these. See our guide on why DCP setbacks for granny flats differ by council.
Your council's DCP may add more
While the SEPP sets statewide baseline standards, each council's DCP can add controls for secondary dwellings. Common DCP additions include:
- Larger rear setbacks than the SEPP 3 m minimum
- Separation distances between the main dwelling and the granny flat
- Additional landscaping or deep soil planting requirements
- Materials and finishes to match the streetscape character
- Specific waste storage and collection arrangements
DCP controls apply to the DA pathway. For the CDC pathway, the SEPP standards take precedence — but understanding DCP requirements matters if you need to go through DA, or if you want your build to align with council expectations.
You can browse your council's DCP controls using PlotDetect's DCP browser.
Frequently asked questions
Can I build a granny flat bigger than 60 m²?
Not under the SEPP Housing 2021 complying development pathway. The 60 m² cap applies regardless of lot size. Some councils may consider larger secondary dwellings via DA in specific circumstances, but this is council-dependent and not guaranteed.
Can I rent out a granny flat?
Yes. Secondary dwellings approved under the SEPP can be rented out. The previous 10-year moratorium on separate sale of secondary dwellings has been lifted for some lot configurations, but most granny flats remain tied to the primary lot title.
Do I need council approval for a granny flat?
You always need either a CDC (issued by a private certifier) or a DA (issued by council). You cannot build a granny flat without one or the other. The CDC pathway is faster and does not require council assessment, but requires meeting every SEPP standard.
What zones allow granny flats in NSW?
R1 General Residential, R2 Low Density Residential, R3 Medium Density Residential, and RU5 Village. R4 High Density Residential does not permit secondary dwellings under the SEPP Housing 2021.
How do I check if my property is eligible?
You need to verify your zone, lot size, and check for exclusion constraints (heritage, flood, biodiversity, acid sulfate, strata). PlotDetect's eligibility checker runs these checks automatically for any NSW address.
Check your property in 30 seconds
PlotDetect checks zone, lot size, heritage, flood, and environmental constraints for any NSW address. Enter your address to see whether your property qualifies for a granny flat under the SEPP Housing 2021 CDC pathway.