Do You Need Council Approval for a Granny Flat?
Most granny flats built in NSW are never assessed by council. They are approved by a private certifier under the complying development rules in the Housing SEPP, and council’s involvement is limited to issuing a planning certificate and, later, sending you a rates notice. That surprises a lot of homeowners who assume a second dwelling in the backyard must mean a long council process. It can, if the block has a problem, and we will get to those. But the default answer for a standard residential lot is no, you do not need council approval. You need an approval, and there is a big difference.
Why most granny flats never go to council
NSW has three approval pathways for building work. Exempt development needs no approval but is limited to minor work, and a dwelling is never exempt. A Development Application is assessed by council against its own Local Environmental Plan and Development Control Plan, with neighbour notification and a merit assessment that takes months. In between sits complying development: a set of fixed, statewide rules, and if the proposal meets every one of them a Complying Development Certificate must be issued, by a private certifier or by council, usually within weeks. The Housing SEPP puts secondary dwellings squarely in that middle pathway. The state government wrote the rules so that a granny flat on an ordinary block could be approved without a merit assessment, and that is how the vast majority get built.
The rules the certifier checks instead
A certifier is not waving the job through. They check the proposal against the Housing SEPP and the Housing Code item by item, and if one fails they cannot issue the certificate. The main tests are the lot area, which must be at least 450 m², the zoning, which must be residential, the limit of one principal dwelling and one secondary dwelling on the lot, and the 60 m² cap on the flat’s internal floor area. Then come the physical controls: side setbacks of generally 0.9 m, a rear setback of 3 m on lots up to 900 m², a maximum building height of 8.5 m, and rules on private open space, landscaping, privacy and site coverage. The flat also needs a BASIX certificate and structural engineering, and the lot must not carry the exclusions, such as heritage listing or certain flood and bushfire categories. The numbers here are the common ones, and your certifier will confirm which apply to your block.
When council does get involved
The job goes to council as a DA when the lot or the design falls outside the complying development rules. The usual reasons are a lot under 450 m², a lot in a non residential zone, a heritage item or conservation area, flood or bushfire categories that the Housing Code excludes, a design that wants more than 60 m² or tighter setbacks than the Code allows, or an irregular lot where the controls simply do not fit. A DA is slower and less certain, because council assesses on merit and neighbours get a say, but it is also more flexible. We have seen councils approve a granny flat on a lot that the complying development rules would reject outright. If your block has one of these issues, the DA is a path, not a wall.
The things council touches even on a CDC job
Even when a private certifier issues the approval, council does not disappear. You order the Section 10.7 planning certificate from council, and it is the document that shows the zoning and the constraints. If a tree needs to come out for the footprint, the tree permit comes from council. Connecting the stormwater to the kerb or a council pit needs council’s consent and often a road opening permit. Some councils charge a developer contribution on secondary dwellings, which the certifier collects as a condition of the CDC. And once the Occupation Certificate is issued, council is notified and your rates will reflect the second dwelling. None of this is an assessment of the design. It is the ordinary business of building on a block in a council area.
The shed that became a flat: why skipping approval does not work
Every so often someone asks whether they can build a large shed under the exempt rules and fit it out as a flat later. The honest answer is that it does not work. A shed is exempt because it is not habitable. The moment it has a kitchen and a bathroom and someone sleeps in it, it is a dwelling without approval, and council can order it demolished or returned to a shed. Unapproved dwellings also sit outside the Home Building Compensation Fund, void most insurance, cannot legally be rented, and will be picked up by a buyer’s conveyancer when you sell. The complying development pathway exists so you do not need to take that risk. It is faster than most people expect and the certifier’s fee is a small fraction of the build.
Converting a garage or part of the house
Turning an existing garage or a wing of the house into a secondary dwelling follows the same logic. It is still a change of use to a dwelling, so it needs a CDC or a DA. The upside is that the Housing SEPP allows a secondary dwelling located entirely within an existing house to be considered even on a lot under 450 m², which is useful on smaller blocks. The downside is that an old garage was never built as a dwelling. The slab usually has no moisture barrier or insulation, the frame may not meet bracing and tie down requirements, and the whole thing has to be brought up to the current NCC for a habitable building, including the energy provisions. We often find that a new detached flat costs little more than a serious conversion and ends up a better building.
How to get a straight answer in a week
Three things settle the approval question for almost any block. The Section 10.7 certificate for the zoning and the constraints. A copy of the title and the deposited plan, which shows the lot area, the easements and any covenants or restrictions. And a walk around the yard with someone who knows the Housing Code, to check whether a 60 m² footprint fits inside the setbacks with usable open space left for both dwellings. If those three line up, you are on the CDC path and a certifier can confirm it in writing. If one does not, you know early and can decide whether a DA is worth pursuing.
Decide the pathway before the design
We will not draw a granny flat until we know which pathway it is on, because a plan designed for a CDC and then pushed into a DA, or the reverse, wastes weeks and money. Leds Design reads the certificate and the title, checks the yard, and tells you plainly whether you are looking at a certifier in a few weeks or council in a few months. The design is then drawn to that pathway and costed on the cost sheet before it goes anywhere, so the flat that gets approved is the one you can afford to build.
This article is general information for homeowners in NSW and is not legal, financial or engineering advice. Planning rules, building standards and prices change, and every block and house is different, so confirm anything that matters for your project with your builder, certifier or council before you commit.
