Yes, a granny flat in NSW needs approval, but probably not in the way you're picturing. A lot of people assume it means a long, uncertain council process. For most granny flats it doesn't, because NSW has a faster approval path designed specifically for them. This post explains the two paths, the rules that decide which one you're on, and what the whole thing actually involves.
A granny flat is officially a "secondary dwelling," and the rules sit in a state housing policy that applies across NSW. We build them across Wollongong, the Illawarra and the Southern Highlands, and managing the approval is part of what we do, so here's the version we'd give you over a cuppa on site.
The two approval paths
There are two ways to get a granny flat approved in NSW, and which one applies to you depends on whether your block and design comply with the state rules.
CDC: the fast path
A Complying Development Certificate, or CDC, is the path most granny flats take. If your block and your design tick every box in the state policy, a private certifier can approve it without it going through a full council assessment. It's faster, often signed off in around 20 days once the documents are complete, and it's more predictable because the rules are spelled out clearly. You're not at the mercy of a merit-based decision, you're checking your design against a fixed list and getting a yes when it complies.
DA: the council path
If your site doesn't fit the complying development rules, your granny flat goes as a Development Application, or DA, through your local council. A DA is assessed on its merits, takes longer, and usually needs more reports and higher fees. Things that push you onto the DA path include an undersized or oddly shaped block, heritage listing, flood-prone or bushfire land, or other environmental constraints. A DA isn't a dead end, plenty of granny flats are built this way, it's just a longer and less certain road.
The single most useful thing you can do early is work out which path you're on, because it shapes your timeline and a chunk of your cost.
Can you build a granny flat without council approval?
You can build one without going to council, but not without approval. If your block and your design tick every box in the state policy, a private certifier issues the certificate and council never assesses it. That's what most people are really asking about when they search for a granny flat with no council approval, and it's the path most builds around Wollongong take.
What you can't do is skip approval altogether. An unapproved secondary dwelling is a problem you keep paying for: it's hard to insure properly, awkward to rent, it surfaces the moment you sell, and council can order changes or removal. Anyone offering to build one without approval is selling you a headache, not a shortcut.
The exception people have heard about is a shed or studio with no kitchen or bathroom. In NSW that generally isn't a secondary dwelling and sits under different rules. The moment it can be lived in as a self-contained home, it's a granny flat and it needs the certificate.
What if there's already an unapproved granny flat on the block?
An existing unapproved granny flat in NSW can usually be sorted, but it has to go through council, and there are two ways to do it. The first is a development application for the work that's already been built, which council assesses as if it were proposed, and which can require changes before it's approved. The second is a building information certificate, which doesn't approve the use but confirms council won't order the building demolished, altered or repaired for seven years.
Which one you need depends on what you want from it. If the flat is rented, or you want it recognised as a secondary dwelling when you sell, it needs the DA. If it's a studio or a converted garage and the question is only whether council will make you pull it down, the certificate answers that, and it's also what a buyer's solicitor will ask for.
Either route starts with a survey and a report from a building professional, and unapproved work built to a poor standard may need rectifying first. It comes up most often when a house is bought with a flat already out the back and nothing on file for it, so if you're buying, ask for the approval before exchange.
The key rules that decide it
The state policy sets out the conditions a granny flat has to meet to qualify for the complying development path. The headline ones most blocks come down to are:
- Minimum lot size. Your block generally needs to be at least 450 square metres to add a secondary dwelling under the complying development rules.
- Maximum size. The granny flat can have up to 60 square metres of internal living area. Covered patios, decks and carports are counted separately within their own limits, so the total usable area is often a bit more than 60 metres.
- One per lot. You can have one secondary dwelling per block, in addition to the main house.
- Setbacks. The flat has to sit a set distance from the boundaries, which depends on your block size and zone.
- Same title. The granny flat stays on the same lot as the main house and isn't subdivided off under the standard rules. It can be rented to a separate household, which is why so many are built for income.
These are the broad strokes. The fine detail depends on your zone and your specific block, so the first real step is always checking your site against the rules rather than assuming it complies, or assuming it doesn't.
Can I build a granny flat on my property in NSW?
In NSW, generally yes, if your block is at least 450 square metres, sits in a residential zone that permits secondary dwellings, doesn't already have one, and leaves room for the flat inside the setbacks with sewer and drainage it can connect to. Plenty of standard Illawarra blocks clear all of that without drama.
The blocks that don't usually have one specific catch:
- Under 450 square metres, or a battleaxe or odd shape that leaves nowhere compliant to put the building.
- An easement, a sewer main or a big protected tree sitting in the only spot it would fit.
- Heritage, flood or bushfire mapping over the site.
- A zone that doesn't allow a secondary dwelling at all, which no amount of land area fixes.
None of those kill the idea outright. Most push you onto the DA path or a redesign rather than off the block entirely. The numbers your design has to work inside are in our granny flat size and setback rules guide, and if a one-bedroom is what you're picturing, 1-bedroom granny flat floor plans shows what fits.
What the approval process involves
Whichever path you're on, getting to approval means putting together a proper set of documents: a site plan, the dwelling design and floor plans, engineering for the footings and structure, and any reports the site needs, like a stormwater plan or a BASIX certificate for energy and water. For a CDC, a private certifier checks all of that against the policy and issues the certificate. For a DA, council assesses it and may ask for changes or extra information before approving.
It sounds like a lot, and on your own it can be, because you're coordinating a designer, an engineer and a certifier and making sure they all line up. That's the part we take off your plate. We handle the design, the engineering and the approval as one process, so you get a single point of contact instead of chasing separate people.
The honest takeaway
Most granny flats in NSW can be approved through the faster CDC path, and that's good news for both your timeline and your budget. But it hinges on your block meeting the rules, so the smart first move is a proper check of your site before you get too far down the road. If it doesn't comply, a DA is still very doable, it just takes longer.
If you'd like a hand working out which path your block is likely to take, that's where we start every granny flat. For the wider rules and what a good builder handles end to end, see our guide to building a granny flat in NSW, and for how we run the whole job, our granny flat build page. When you're ready, call us on 0434 037 851 or get in touch through the contact page for a free quote.
Want a hand with this at your place? Get a free quote or call 0434 037 851.