Every granny flat in NSW needs an approval before building starts. There are 2 ways to get one. A complying development certificate (CDC) comes from a private certifier and usually takes 4 to 6 weeks. A development application (DA) goes to your council and typically takes 3 to 6 months. About 9 in 10 granny flats go the CDC way. We manage both in-house, so you do not lodge anything yourself.
| Question | Fast pathway (complying development) | Council pathway (development application) |
|---|---|---|
| Who decides | A private certifier | Your council |
| What they check against | The state Housing SEPP checklist | The council’s local plan and development control plan |
| Does Council’s DCP apply? | No | Yes, in full |
| Can it be refused if you comply | No | Yes, it is assessed on merit |
| Typical time | 4 to 6 weeks | 3 to 6 months |
| Developer contribution | Payable, before work starts | Payable, before your construction certificate |
Fast pathway
(complying development)
Who decides
A private certifier
What they check against
The state Housing SEPP checklist
Does Council’s DCP apply?
No
Can it be refused if you comply
No
Typical time
4 to 6 weeks
Developer contribution
Payable, before work starts
Who decides
Your council
What they check against
The council’s local plan and development control plan
Does Council’s DCP apply?
Yes, in full
Can it be refused if you comply
Yes, it is assessed on merit
Typical time
3 to 6 months
Developer contribution
Payable, before your construction certificate
The row that matters most is the DCP row. A development control plan is the council’s own rulebook. On a CDC the certifier does not apply it. That is why a block that suits a granny flat under the state rules can still run into trouble at council.
Your block has to meet every standard in the state rules. The main ones:
a lot of at least 450 m²
at least 12 m wide at the building line, for a lot of 450 to 900 m²
(wider for bigger lots)
a residential zone, R1 to R4 (R5 large lot residential is excluded)
a granny flat of no more than 60 m² of floor area
no basement and no roof terrace
Setbacks and landscaped area step up as the lot gets bigger.
The NSW granny flat rules page has every figure.
If your block misses any CDC standard, the granny flat goes to council as a DA instead. Common reasons are a lot under 450 m², a narrow frontage, or land affected by flood, bush fire or heritage. A DA is not a refusal. It means council assesses the design on its merits, with its own controls. Our page on what happens if your block does not meet CDC covers the options.
Some councils add local rules that only apply on a DA. Your council’s page on our site sets them out.
Neither path can start until the paperwork is ready:
| Step | Typical time |
|---|---|
| Site assessment and fixed price | 1 to 2 weeks |
| Design and selections | 2 to 4 weeks |
| Survey, soil test and engineering | 2 to 4 weeks |
| BASIX certificate and final drawings | 1 to 2 weeks |
This is the part people forget to count, and it often takes longer than the certifier. You will see CDCs quoted at 10 to 20 business days. That comes from certifier practice, not the law, and it assumes a complete application.
Approval and certification are not in our base build price. We quote them with the other site costs after the site inspection, in writing. Your council also charges a development contribution on both paths, and several councils set it by bedroom count. Across most Sydney blocks, plans and approvals, council fees and non-standard site works come to $14,000 to $39,000. The cost guide breaks it down.
You need an approval, but not always from council. If your block meets the state standards, a private certifier can approve it as complying development. Council only decides when it goes as a DA.
A CDC usually takes 4 to 6 weeks once it is lodged, and a DA typically takes 3 to 6 months. Before either can be lodged, the site assessment, design, survey, soil test, engineering, BASIX certificate and final drawings need to be ready, which usually takes another 6 to 12 weeks.
If your block and the design meet every standard in the state rules, the certifier cannot refuse the CDC on merit. It can still be delayed if the application is incomplete, or if the site turns out to miss a standard, for example because of flood, bush fire or heritage.
We do. At the site assessment we check your lot size, frontage, zoning and any flood, bush fire or heritage affectation, and tell you whether your block can go CDC or needs a DA. We then manage the approval in-house.
Either can approve a granny flat. If your block meets the state standards, a private certifier issues a CDC and council does not assess it. If it does not, the application goes to council as a DA.
Usually yes, but generally not as a CDC. Heritage land is one of the common reasons a granny flat goes to council as a DA, where it is assessed against the council’s heritage controls.
Check whether your block qualifies,
or call BlueGum on 1300 060 651 to book a site assessment.
Or call our team on 1300 060 651
Building granny flats since
Since 2012
Builder licence
247388C, verifiable through NSW Fair Trading
Industry body
Housing Industry Association member
MBA NSW Excellence in Housing Awards
Winner 2021, Winner 2023, Finalist 2020
Completed granny flats documented on this site
70+
Approvals
CDC and DA, both managed in-house
Pricing
Fixed price after a site assessment, 2-bedroom from $134,990
Building granny flats since
Since 2012
Builder licence
247388C, verifiable through NSW Fair Trading
Industry body
Housing Industry Association member
MBA NSW Excellence in Housing Awards
Winner 2021, Winner 2023, Finalist 2020
Completed granny flats documented on this site
70+
Approvals
CDC and DA, both managed in-house
Pricing
Fixed price after a site assessment, 2-bedroom from $134,990
