Retaining walls
A retaining wall holds soil back. A dividing fence marks a boundary. They can stand in the same place and look like one structure, but the law treats them as different things, and that difference decides who pays.
General information, not legal advice. This page sets out how the law generally applies. It does not take account of your circumstances, and you should get advice about your own situation before acting on it. The official sources this page is written from are listed on it; where they differ from anything here, they are the authority.
Why nobody can tell you the answer in one sentence
Retaining wall disputes are the ones where people have usually already been given three confident and contradictory answers. That is not because anyone is being careless. It is because there is no statute that sets out, in the way the Dividing Fences Act 1991 does for fences, a default rule about who pays for a retaining wall.
The first thing to establish is what the structure actually is. A dividing fence separates the land of adjoining owners. A retaining wall holds soil back so that land at different levels stays where it is. If the structure’s real function is to retain, the equal-sharing starting point that applies to a sufficient dividing fence does not simply apply to it. Where a fence sits on top of a retaining wall, you can have both: a fencing question about the fence and a quite separate question about the wall underneath.
The second thing is why the wall is there. A wall that exists because one owner cut into or filled their own land, so that their neighbour’s soil needed holding, sits very differently from a wall that has simply always been part of a natural slope. The general law expects a landowner not to remove support from a neighbour’s land, and a great deal follows from who altered the ground.
The third thing is what the documents say. A development consent may have imposed conditions about who was to build and maintain the wall. The title may carry an easement or a covenant that does the same. Those documents beat everybody’s memory, and getting them is usually the cheapest useful step you can take.
What the work actually is
Identifying what the structure is
Retaining wall, dividing fence, or a fence sitting on a wall. This is not word-play. It decides which body of law applies and therefore who is likely to pay for what.
Finding out how it came to be there
Council records, development consents, building approvals and older plans. Who altered the level of the land, and when, is frequently the fact the whole dispute turns on, and it is usually recorded somewhere.
Reading the title properly
Whether an easement, a covenant or a positive covenant imposes a maintenance obligation on one owner. Where one exists, the argument is usually over quickly.
A realistic view on cost
Retaining walls are expensive and these disputes can become expensive faster than the repair. We will tell you when the sensible course is a negotiated contribution rather than a contest about principle.
Questions people ask first
Do we split the cost of the retaining wall fifty-fifty, like a fence?
Not automatically. The equal-sharing starting point in the Dividing Fences Act 1991 is about a sufficient dividing fence, and a wall whose function is to retain soil is generally not a dividing fence. Responsibility for a retaining wall is worked out from how and why it was built, from any consent conditions, from anything recorded on title, and from the general law about support. An even split can still be the sensible commercial outcome — it is just not the legal starting point.
There is a fence on top of the wall. Does that change things?
It can mean you have two structures and two questions. The fence on top may be dealt with as a dividing fence under the Dividing Fences Act 1991, which has its own process and its own forum, while the wall below is dealt with on a different basis. It is worth separating them early rather than negotiating over one lump sum for both.
The wall is on my neighbour's side of the boundary. Is it their wall?
Location is relevant but it is not the whole answer. Which land the wall sits on matters, and so does whose land it supports and who altered the level of the ground in the first place. You will not get far on this question without knowing where the boundary is, so this often becomes a boundary question first.
My neighbour excavated and now my land is slipping.
That is a serious and separate problem, and it is not one to sit on. The general law expects a landowner not to remove the support their neighbour’s land enjoys. Photograph what is happening, record the dates, and get advice quickly — both because the position can worsen and because evidence about the state of the ground gets harder to gather as work continues.
The wall is failing but my neighbour says it is fine.
Get an engineer rather than an argument. A structural opinion about the condition of the wall, and about what is causing it, turns a difference of view into something that can be acted on. It is also the document most likely to make a reluctant neighbour, or their insurer, take the matter seriously.
Which court or tribunal does this go to?
It depends entirely on how the claim is framed. Some retaining wall disputes are ordinary civil claims and belong in a court; where there is a fencing component, that part may go to NCAT or the Local Court under the Dividing Fences Act 1991. Because the forum is not fixed, this is a matter worth taking advice on before lodging anything.
Is a retaining wall ever the council's responsibility?
Where a wall supports or adjoins public land, a road or a drainage reserve, the relevant authority may have obligations, and that is worth checking before you assume it is a dispute between two households. Start by asking the council what its records show about the wall and about any consent under which it was built.
What to have ready
Retaining wall disputes are won and lost on records about how the ground came to be the shape it is.
- Photographs of the wall, including any cracking, leaning or movement.
- Anything an engineer, builder or landscaper has said about its condition.
- Your title documents, and any easement or covenant noted on them.
- Any development consent or building approval covering the wall or the earthworks.
- What you know about when the wall was built and by whom.
- Whether either property has been cut, filled or excavated, and when.
- Repair quotes, and what they actually include.
- Any correspondence with the neighbour about the wall, with dates.