Ownership and responsibility for retaining walls aren’t always as straightforward as they seem. Many people assume the same rules apply as they do for standard fences, but that’s not quite the case. Under the Neighbourhood Disputes Act 2011, retaining walls are treated differently, often leading to confusion and conflict between neighbours. So, who is responsible for a retaining wall in Australia?
At the heart of it, the general rule is this: the person who benefits from the retaining wall is usually the one responsible for maintaining and repairing it. While this sounds straightforward and simple things get tricky when the wall sits on a boundary line or supports multiple properties. So, who counts as the beneficiary then?
At Level Up Surveying, we see these kinds of situations all the time, and we know how important it is to have clear information and guidance when navigating property boundaries and retaining wall disputes.
In this article, we break it all down for you: what retaining walls are, who’s responsible for them, how state laws differ, and what to do if you find yourself in a disagreement. Whether you’re planning to build, repair, or simply want to avoid future headaches, we will give you the clarity and confidence you need to make an informed decision.
What is a Retaining Wall?
Unlike typical fences, retaining walls are strong structures that hold back soil from the sides. These walls let you keep ground at different levels on both sides. They are engineered structures that are built to resist the sideways pressure of soil, especially when the land is sloped or uneven. The more earth that’s piled up behind the wall, the more pressure it needs to withstand.
A well-built retaining wall can fix or prevent a range of problems by:
- Controlling erosion
- Improving drainage
- Creating flat, usable space on sloped land
- Helping protect foundations from soil movement
Who is Responsible for A Retaining Wall?
Retaining wall disputes between neighbours are more common than you might think and usually stem from the question: Who’s responsible for it? While it can feel like a grey area, the law in Australia does offer some guidance to help you navigate the situation fairly.
The General Rule of Thumb in Australia
Australian law makes this basic principle clear: whoever alters the natural ground level assumes responsibility for necessary retaining walls. Legal precedents state that “each owner is responsible for retaining the portion of earth that they (or the previous land owner) altered from the natural ground level”. This rule applies even if you buy property where someone else has made these changes.
Property owners can change their land as they wish (within development rules), but they must support neighbouring natural land. In legal terms, removing the support of natural land is considered a “legal nuisance” with strict liability. That means you don’t need to prove your neighbour was careless – if their actions caused your land to become unstable, they’re legally accountable.
Are Retaining Walls Treated Like Fences?
Not quite. While fences and retaining walls might look like they serve similar purposes, they’re treated differently under Australian law.
In QLD, retaining walls aren’t covered by the Dividing Fences Act, unless the wall was specifically built to support a fence. Even if removing the wall would cause the fence to fall over, that alone doesn’t count.
Instead, retaining walls fall under building codes, common law, and encroachment legislation. If a wall crosses into your neighbour’s property, it may be classed as an encroachment, which could lead to legal action, boundary adjustments, or compensation.
Shared Benefit: Who Pays Then?
Sometimes, a retaining wall doesn’t just benefit one property, but the neighbouring property as well. This is especially common when one neighbour has raised their ground level and the other has lowered theirs. In these cases, the wall plays a role in stabilising the land on both sides, which means both parties may share responsibility (and costs) for building and/or maintaining it.
When a retaining wall offers a shared benefit, it’s usually fair to split the costs based on how much each property gains from the wall. Ongoing maintenance and any future repairs should also be considered in this cost-sharing arrangement.
Avoiding Disputes With Clear Agreements
When it comes to retaining walls, especially those on/near shared boundaries, a written agreement can make all the difference. Having a clear, written agreement with your neighbour can cover important details like where the boundary lies, who’s responsible for ongoing maintenance, and how the costs will be shared if both properties benefit from the wall.
Even for smaller projects, it’s worth putting everything in writing. It gives everyone peace of mind and provides a clear plan if questions or issues come up later.
A written agreement should ideally cover:
- Who pays for the initial building costs (or how building costs are shared)
- How ongoing maintenance will be handled
- What happens if the wall needs repairs in the future
If the wall is damaged due to negligence, for example, poor drainage, heavy equipment, or modifications by one party, the affected neighbour might want to seek compensation to cover the repair costs. In these situations, be sure to keep clear records to help avoid confusion:
- Detailed records of any agreements
- Copies of quotes, receipts, and invoices
- Photographic evidence of the wall before and after works or damage
- Written communication with your neighbour (texts, emails, letters)
Building a Retaining Wall During Construction or Renovation
If you’re planning a new build, extension, or landscaping project that affects the ground level, you’ll likely be the one responsible for the retaining wall. Here’s what you should do when planning such projects:
- Speak with your neighbours early: Open communication helps avoid future disputes.
- Consider a joint retaining wall: This can be more efficient and cost-effective than building two separate walls.
- Put everything in writing: Agree on who will pay for what, and how future maintenance will be handled.
- Check local council requirements: Councils may have specific rules or approvals needed for retaining walls, especially near boundaries.
Don’t Guess. Check with Your Council
While these rules offer a good starting point, laws can vary depending on where you live. That’s why it’s always a good idea to speak with your local council or a property professional before making changes, or if you find yourself in a retaining wall dispute.
What if a Retaining Wall Collapses or Fails?
When it comes to maintenance and repairs of retaining walls, it’s worth understanding your responsibilities ahead of time to avoid disputes down the track, especially when something goes wrong. Whether you’re dealing with an aging structure, signs of damage, or a complete collapse, understanding who’s responsible is key to resolving the issue smoothly and safely.
Who’s Responsible When a Wall Fails?
In most cases, the owner of the land where the retaining wall is located is responsible for its maintenance and repair as they are legally required to ensure the wall remains safe and doesn’t pose a risk to neighbouring properties. This rule applies when the wall sits entirely on private land and within clearly defined property boundaries.
But what if someone else causes the damage?
In these cases, your neighbour may be liable to cover repair or replacement costs. For example, if they install a new drainage system that redirects water toward your retaining wall, use heavy machinery near the boundary, or carry out landscaping that destabilises the wall’s structure, they may be legally responsible for the resulting damage. However, the key is showing that their actions directly caused the damage.
What If the Wall Sits on a Boundary or Affects Neighbours?
If the wall is built along a shared boundary or provides lateral support to a neighbouring property, responsibility can become shared. Here, collaboration is often necessary to address issues fairly and avoid disputes. That means when a retaining wall collapses and causes damage or removes support from nearby land, it’s possible for liability to extend beyond just the owner of the land it sits on.
In these situations, it’s important to:
- Confirm ownership of the wall: This is done through property documents or a professional boundary assessment.
- Understand the wall’s structural role: Is it critical in preventing erosion or soil movement?
- Consult local council regulations: This may require you to take action if the wall becomes a safety hazard
Ongoing Responsibilities for Property Owners
To ensure the retaining wall remains safe and structurally sound, property owners are required to take proactive steps to maintain their retaining walls. This includes:
- Inspecting the wall regularly for cracks, leaning, or erosion
- Repairing any damage promptly to prevent further issues
- Ensuring proper drainage behind the wall to reduce pressure from water build-up
By staying on top of these tasks and communicating with your neighbours if the wall is shared, you can help protect your property and maintain positive relationships.
Council Approvals and Building Codes
If you are thinking about building a retaining wall, it is important to know that there is more to the process than just choosing materials and hiring a contractor. Depending on your location and the size of the wall, you might need council approval or a building permit before you can begin.
Every state and council in Australia has its own rules, but as a general guide in Qld, you’ll likely need approval if your retaining wall:
- Is over 1 metre high in
- Sits on or near your boundary line
- Is within 1.5 metres of a building or another retaining wall
- Will support extra weight (this is called “surcharge loading”)
- Is part of pool fencing
- Is built over utilities like sewer or stormwater drains
- Falls within coastal or waterfront zones
Even if your wall is under the height limits, it still needs to follow the National Construction Code. That’s why it’s a smart move to check in with a licensed contractor, engineer, or building certifier before getting started.
What If You Build Without Approval?
Building without proper approvals can lead to serious problems. Local councils can take several actions:
- Hefty Fines: Councils can hit you with financial penalties for unauthorised works.
- Demolition Orders: You could be required to modify or remove the wall completely.
- Insurance Issues: If something goes wrong, your insurer may not cover damage caused by an unapproved wall.
- Legal Liability: If a non-compliant wall fails and damages a neighbour’s property, you could end up footing the legal bill.
- Property Sale Headaches: When it comes time to sell, you’ll need to declare any unapproved structures, which can affect buyer confidence and property value.
Why a Survey Matters
Before you start building (or fixing) a retaining wall, getting a boundary survey done is a smart investment. It might seem like a small detail, but it can save you a lot of time, money, and potential disputes down the line.
A licensed surveyor can carry out a boundary survey to:
- Confirm exactly where your boundary lines are
- Check if there are any existing encroachments
- Clarify which property the retaining wall is actually supporting
- Help resolve any boundary or ownership disputes that may already be bubbling away
This survey marks the exact corners and borders of your property as building or repairing on assumptions or guesswork can lead to costly fixes, or worse, the need to move or rebuild the wall completely.
Local councils often have strict requirements when it comes to retaining walls so proper survey helps make sure your project is fully compliant with local rules and provides your builder with accurate information to work from.
Key Takeaways
Retaining walls might seem like straightforward structures, but when it comes to property boundaries, council rules, and shared responsibilities, it is more complex than many property owners think. Taking the time to understand your obligations, get the right approvals, and involve qualified professionals is the best way to ensure everyone is protected.
With the right approach, you can avoid future disputes, keep your property secure, and protect your investment for years to come. At Level Up Surveying, we’re here to help you start strong, with precise boundary insights and expert advice tailored to your project. Get in touch today to get started.
