Why your council's DCP setbacks for granny flats are different
The SEPP Housing 2021 sets statewide minimums for granny flat setbacks for a granny flat built as complying development, and those setbacks grow with lot size and building height. If the granny flat goes through a development application instead, your council's Development Control Plan also applies — it can set larger setbacks, separation distances and landscaping rules that reduce what you can actually build. The same lot can have a very different buildable envelope depending on which council it falls under. To see the setbacks for your own lot, use the granny flat check.
Same lot, different buildable footprints
The same typical suburban lot with an existing dwelling at the front. Footprints are relative and illustrative; the controls themselves are set by the SEPP and your council's DCP.
Complying development (Housing SEPP 2021), single-storey granny flat
Council A (topic-based DCP)
Council B (dev-type DCP)
These are simplified examples to show how DCP setbacks reduce buildable area. Actual controls vary by council, precinct, and lot characteristics. Two-storey builds have different side setback requirements.
What the SEPP says vs what DCPs add
The SEPP Housing 2021 sets minimum standards for secondary dwellings approved as complying development. These are statewide — every council in NSW applies the same SEPP. But councils also adopt their own DCPs, which can impose additional controls for secondary dwellings assessed through the DA pathway.
Complying development standards for a secondary dwelling (Housing SEPP 2021)
| Control | SEPP standard | Notes |
|---|---|---|
| Rear setback | A minimum set by lot size, larger on bigger lots and taller buildings | Grows with building height above a set point, up to a cap set by lot size |
| Side setback | A minimum set by lot size, plus an extra amount for height above a set point | The setback depends on lot area and height, not on the number of storeys |
| Separation from main dwelling | No separation distance specified | Some DCPs set one for a DA |
| Landscaped area | A share of the lot that rises with lot size | Part of it must be behind the building line to the primary road |
| Private open space | A minimum area, which can be shared with the main dwelling | The SEPP also sets its minimum width and access |
| Car parking | No additional space required | A DCP may set a parking rate for a DA |
| Maximum height | A maximum height above ground level that keeps it low-rise | A DCP or LEP may set a different limit for a DA |
| Design / materials | Not specified | Heritage areas may require specific materials, colours, roof pitch |
The most impactful DCP addition is usually the separation distance between the main dwelling and the granny flat. The SEPP does not specify a separation distance. When a DCP sets one for a DA, combined with the rear setback, the buildable area shrinks — most of all on smaller lots.
Why councils have different controls
DCPs are adopted by individual councils to reflect local character, built form priorities, and environmental context. Councils with predominantly low-density, large-lot suburbs may set generous setbacks and landscaping requirements. Councils with tighter inner-city lots may accept smaller setbacks to make secondary dwellings feasible.
There is no statewide standard for DCP content. Each council writes its own, and they are structured differently. Some councils organise DCP controls by development type (a dedicated “secondary dwellings” chapter). Others use topic-based organisation where setback controls apply universally to all residential development, including secondary dwellings.
Three DCP structural types in NSW
The structural type determines how you find the controls that apply to your build. Topic-based DCPs are the hardest to navigate because the relevant provisions are scattered across multiple sections.
Merged councils: several DCPs in one council
The 2016 NSW council amalgamations created a particular challenge for DCP navigation. Merged councils often still operate under the former council's DCP for each geographic area. The controls that apply to your property depend on which former council area your lot falls within — not the current council name.
Example: Inner West Council
Inner West Council was formed from three former councils. Each former area still operates under its own DCP:
Former Ashfield
Ashfield DCP 2007 — Development-type organised
Dedicated secondary dwelling chapter with specific setback tables
Former Leichhardt
Leichhardt DCP 2013 — Topic / universal
No dedicated secondary dwelling chapter; universal residential setbacks apply
Former Marrickville
Marrickville DCP 2011 — Zone organised
Secondary dwelling controls within low-density residential section
A property on one side of a street may be under a completely different DCP than the property across the road, even though both are in the same council area.
What happens when SEPP and DCP conflict
This is a common point of confusion. The answer depends on which approval pathway you use:
CDC pathway (complying development)
The SEPP standards apply. DCP controls are not part of the CDC test, apart from the DCP's stormwater requirements where no separate drainage approval is needed. A certifier can issue the CDC only if the build meets every complying development requirement, including that stormwater requirement where it applies, and the property is not excluded.
DA pathway (development application)
Both the LEP and the DCP apply. Council assesses the application against their DCP controls, which may require larger setbacks, more landscaping, or additional parking. Council has discretion to vary DCP controls, but this is not guaranteed — the DCP is the starting point for assessment.
In practice, this means homeowners whose properties qualify for CDC get a more predictable outcome: the statewide SEPP standards apply, and council DCP variations are irrelevant. Homeowners who must go through DA — because of heritage, flood, or other exclusions — face council-specific DCP requirements on top of the SEPP framework.
How to find your specific DCP controls
Finding the secondary dwelling controls in your council's DCP is not always straightforward. Depending on the DCP structure, the relevant provisions may be in a dedicated chapter, scattered across topic-based sections, or embedded in zone-specific controls.
1. Check your council's website
Most councils publish their DCP as a PDF or web document. Search for “secondary dwelling” or “ancillary dwelling” in the document. If your council was created from a merger, make sure you are reading the correct former-council DCP for your property's location.
2. Use PlotDetect's DCP browser
PlotDetect's DCP browser shows extracted DCP provisions by council, precinct, and development type. For supported councils, you can filter directly to secondary dwelling controls and see the specific setback, height, and landscaping requirements that apply.
3. Speak to a town planner or your certifier
For complex sites (heritage areas, merged council boundaries, precinct-specific controls), a planning consultant can confirm which DCP applies and how the controls interact with the SEPP standards. If you are going through the CDC pathway, your certifier will assess against the SEPP, but understanding the DCP context is still useful for design decisions.
Frequently asked questions
Do DCP setbacks apply if I use the CDC pathway?
No. For complying development, the setbacks come from the SEPP Housing 2021, not the DCP. The one DCP requirement the SEPP brings in is stormwater disposal, where no separate drainage approval is needed. DCP setbacks are assessed under the DA pathway. This is a key advantage of CDC — the statewide SEPP standards are fixed and predictable, regardless of which council you are in.
What is the minimum rear setback for a granny flat in NSW?
For complying development it depends on lot size and height. The SEPP sets a minimum for each lot size band, then adds to it for any building height above a set point. Larger lots have larger setbacks. For the figure on your lot, run the property check. For a DA, the council assesses the setback against its own controls, usually in its DCP, so check those.
Why does my council require a separation distance the SEPP does not mention?
The SEPP does not specify a minimum separation distance between the main dwelling and the secondary dwelling. Councils include separation controls in their DCPs to address privacy, access, and fire safety. This is one of the most common DCP additions and can significantly reduce buildable area on smaller lots.
I am in a merged council area. Which DCP applies?
The DCP of the former council area your property falls within. For example, Inner West Council operates under Ashfield DCP 2007, Leichhardt DCP 2013, and Marrickville DCP 2011 depending on location. Check your property's address against the former council boundaries to determine which DCP applies.
Can council vary DCP controls for my DA?
Yes. DCPs are guidelines, not legally binding standards (unlike LEPs and SEPPs). Council can approve a DA that does not fully comply with DCP controls if they are satisfied the development achieves the objectives of the control. However, this is at the council's discretion.
Find your council's DCP controls
PlotDetect's DCP browser shows extracted provisions by council, precinct, and development type. See the specific setback, height, and landscaping controls that apply to secondary dwellings in your area.