How high can a retaining wall be without council approval?
Short answer
Usually under a metre, with conditions. In NSW a retaining wall is exempt up to 600 mm high and at least 1 m from boundaries. In Queensland it's up to 1 m (including the cut or fill), with no load such as a driveway nearby and at least 1.5 m from buildings. In SA, walls retaining 1 m or less are generally exempt. In Victoria, walls on or next to a boundary need a permit. Anything taller generally needs approval and often an engineer.
Retaining walls are the backyard structure most likely to be underestimated. A wall holding back soil carries far more load than it looks, and a failed wall can damage your property — or your neighbour’s. That’s why the approval limits are low.
Limits by state
| State | Exempt if… |
|---|---|
| NSW | No more than 600 mm high (and no more than 600 mm of cut or fill); at least 1 m from each boundary; at least 2 m from any other retaining wall; at least 40 m from a natural waterbody; not redirecting water onto neighbours |
| QLD | No more than 1 m high including the retained cut or fill; no surcharge load (like a building or driveway) in the zone of influence; at least 1.5 m from a building or another wall |
| SA | Retaining 1 m or less, and the wall plus any fence on top no more than 2.1 m — unless your zone says otherwise |
| VIC | A permit is needed on or next to a title boundary or over an easement; confirm other walls with your council |
| WA | Check with your council — some councils require a permit for quite low walls |
Why the limits are strict
Soil pressure increases quickly with height, and water trapped behind a wall adds even more. Common culprits when walls lean or fail are poor drainage behind the wall, footings too small for the height, and extra load near the top — a driveway, a shed or a fence.
Building an exempt wall properly
Even under the exempt height, build it like it matters:
- Drainage: agricultural (slotted) pipe at the base behind the wall, surrounded by drainage gravel and wrapped in geotextile fabric, running to a legal discharge point.
- Footings: follow the block or sleeper manufacturer’s footing details for your wall height and soil.
- Materials: use sleepers and posts rated for in-ground contact, or engineered block systems.
- Setbacks: the boundary distances above exist partly so you can maintain the wall — and so it doesn’t become your neighbour’s problem.
When you need an engineer
If the wall is over the exempt height, holds back a slope that supports a building or driveway, or is close to a boundary, get engineering advice and approval before you start. It costs far less than rebuilding a failed wall.
For sheds, fences, decks and pergolas, see do you need council approval?
Sources
Every rule on this page is taken from these official sources. If a rule has changed, please tell us and we’ll fix it.
This guide is general information, not legal or professional advice. Rules differ between states, councils and individual properties, and they change. Confirm with your state regulator or council before starting work, and if in doubt, get a licensed tradesperson.