Retaining Walls in NSW: Do You Need Council Approval?
Thinking about building a retaining wall or doing some earthworks on your property? It's one of those jobs that sounds simple but comes with more rules than most people expect. The good news is that, depending on the size and where it goes, you may not need to lodge a full application at all. Here's a plain-English guide to how it works in NSW.
Before you start, a quick word
Retaining walls and earthworks have real potential to affect neighbouring properties, drainage and land stability, which is why the rules exist. The standards below are a general guide only and don't cover every property. Some land has extra restrictions, so it's always worth checking your specific situation before you dig. If you'd like a hand with that, that's exactly what we do.
The three approval pathways
In NSW, a retaining wall or earthworks generally falls into one of three pathways, depending on its size and location.
The first is exempt development. This is minor work that doesn't need any planning or building approval at all. If your wall or earthworks stays within the exempt limits, you can simply get on with it.
The second is complying development. This is a combined planning and building approval that can be issued quickly by a private certifier or council, without a full development application. Larger walls and deeper earthworks often fall into this category.
The third is a development application, or DA. If the work doesn't meet the exempt or complying standards, it generally needs to go to council as a DA for assessment.
Working out which pathway your wall falls into is the first and most important step, because it determines how much time, paperwork and cost is involved.
How high can a retaining wall be?
Height is the single biggest factor in which pathway applies.
As a general rule, if your earthworks or retaining wall stays within 600mm above or below the existing ground level, it may qualify as exempt development, meaning no approval is needed (provided it meets the other conditions further down).
Once you go beyond 600mm above or below ground level, you're generally moving into complying development territory, which means approval from a certifier or council is required.
For complying development, height limits also depend on where the wall sits. Close to a side or rear boundary (within 1m), a wall generally can't exceed 1m in height. Anywhere else on the site, it generally can't exceed 3m. Walls more than 600mm above or below ground level also need to be properly contained by a structural support.
Keeping your distance: boundaries, easements and water
Where you put the wall matters just as much as how high it is.
For exempt development, the work generally needs to be at least 1m from any lot boundary, registered easement, sewer or water main, and at least 40m from any natural water body such as a creek or river.
Easements deserve special attention. A retaining wall or earthworks generally must not be located over a registered easement. Easements often protect things like drainage or services running through your land, so building over one can cause real problems down the track. If you're not sure whether you have an easement, it's worth checking your title before you plan anything.
If you're near a creek, river or other natural waterway, the rules tighten. Within 40m of a natural water body, the maximum depth of excavation is generally limited to 1m.
How deep can you dig?
For deeper excavation, there's a sliding scale that links how deep you can go to how far you are from the boundary. As a general guide:
Up to 1m from a boundary, you can excavate to a maximum depth of 1m.
Between 1m and 1.5m from a boundary, you can go to a maximum of 2m.
More than 1.5m from a boundary, you can go to a maximum of 3m.
In short, the further you are from the boundary, the deeper you're generally allowed to go.
Adding fill to level out your yard
Bringing in fill to create a level area or a platform beside the house is common, but it's also controlled. Fill is generally limited to a maximum height of 1m above the existing ground level.
Where fill is added around a dwelling, it usually needs to be contained either by a retaining wall that doesn't extend more than 1.5m from the external wall of the house, or by a gently sloping embankment that doesn't extend more than 3m from the house and stays more than 1m from a side or rear boundary.
When you'll need an engineer
Bigger walls put more pressure on the surrounding land, so beyond a certain size they need to be signed off by a professional engineer. In residential areas, certification by an engineer is generally required where a wall is more than 600mm above or below ground level and within 1m of a boundary, or more than 1m above or below ground level anywhere else on the site. This is there to make sure the wall is safe and won't fail or damage a neighbour's property.
Drainage and what you can build with
A few practical conditions apply to almost any wall or earthworks.
The work needs adequate drainage and must not redirect water or sediment onto a neighbouring property. Any fill used must be clean (what's called virgin excavated natural material) and free of building or demolition waste. And any wall must be structurally sound, built to the manufacturer's specifications, and comply with the Building Code of Australia.
Separation between walls
There's also a separation rule where you have more than one wall: retaining walls generally need to be at least 2m apart horizontally rather than stacked closely together.
Heritage and sensitive land
Some land comes with extra protections. Retaining walls and earthworks generally can't be carried out on or in a heritage item, and in a heritage conservation area they may only be done as exempt development and only in the rear yard. They also can't be carried out in an environmentally sensitive area. If your property is heritage-listed or environmentally sensitive, the standard rules above may not apply, so it's especially worth getting advice.
A note for commercial and industrial properties
Commercial and industrial sites have their own additional standards. As a general guide, the works can't be carried out on a lot containing a dwelling house or on a flood control lot, can't be within 40m of a natural water body, and can't result in more than 2m of fill on the site. Where a commercial or industrial building adjoins a rail corridor, the works generally need to be set back at least 3m from that boundary.
Where this leaves you
Retaining walls sit in that tricky space where a small job can be approval-free, but a slightly bigger one suddenly needs a certifier, an engineer, or a full application. Getting the pathway right from the start saves you time, money and the headache of building something that later turns out to need approval it never got.
If you're planning a retaining wall or earthworks and you're not sure which pathway it falls under, we're happy to take a look at your property and let you know exactly what's involved before you start.