It’s one of the most common questions people ask before lodging a development application, and the honest answer is: it depends on what you’re doing. But for most projects of any real complexity, the answer is yes, and getting the right survey at the right time can be the difference between a smooth approval process and a drawn-out one.
This post breaks down the three main types of surveys that come up in the DA process, when each one is relevant, and why town planners rely on accurate survey data more than most people realise.
Not all surveys are the same. Each serves a different purpose, and confusing them is a common source of delays and wasted money.
This is the survey most commonly required as part of a DA. A detail and contour survey captures two things: the physical features of the site and the topography.
The detail component records what exists on the site and immediately around it. Buildings, structures, fences, trees, driveways, retaining walls, easements, services where visible, and any other features relevant to how the land is used and how a proposed development will relate to it.
The contour component records the shape of the land, the rises and falls across the site shown as contour lines at regular intervals. For sloped sites this data is critical. It tells the designer, the planner and the council how water moves across the land, where cut and fill will be required, and how the proposed development sits in relation to natural ground level, which directly affects how height is measured and assessed under planning scheme rules.
Together, detail and contour data gives everyone involved in the project a shared, accurate picture of existing conditions. Without it, designs are based on assumptions. Assumptions create problems.
A detail and contour survey is typically required for DAs involving new dwellings, extensions, dual occupancies, subdivisions, and most material change of use applications. If your project has any complexity at all, expect your planner or architect to ask for one early.
A boundary survey defines where your property starts and ends. It identifies the legal boundaries of the lot by locating or re-establishing the survey marks that define them.
People are sometimes surprised to find out that fences, walls and even existing buildings don’t always follow the actual boundary. In older suburbs particularly, structures have been built over decades with varying degrees of accuracy. A fence that looks like it’s on the boundary may be sitting 200mm inside or outside it, and that discrepancy can have significant consequences for a development proposal.
Boundary surveys become important in DA processes where setbacks are tight. Planning schemes specify minimum distances that a building must sit from each boundary, and those distances are measured from the legal boundary, not from where the fence is. If you’re proposing a structure close to a side or rear boundary, having the boundary accurately located protects you from non-compliance issues that only surface at construction stage, or worse, after.
Boundary surveys are also critical in subdivision applications, where the whole point is to redefine where boundaries sit. They’re relevant any time an easement, encroachment, or disputed boundary is involved.
Not every DA requires a formal boundary survey, but if your setbacks are marginal or your site has any boundary ambiguity, it’s worth doing. Finding out the fence isn’t on the boundary after your DA is approved and your building designer has drawn to it is an expensive lesson.
A set out survey happens after a DA is approved, not before. It’s the survey that marks the physical position of a proposed structure on the ground so construction can begin in the right place.
The surveyor takes the approved plans and translates them into physical marks on the site, pegs, profiles or other markers that show the builder exactly where the building footprint sits, where the corners are, and what the levels need to be.
The reason this matters in a DA context is that approval is granted based on specific dimensions and setbacks. A set out survey ensures what gets built matches what was approved. Without it, you’re relying on the builder to interpret plans and measure from features that may themselves not be accurately located. That introduces risk that most builders, certifiers and planners aren’t comfortable with on anything beyond the simplest of projects.
Set out surveys are standard practice on new builds and are increasingly expected on significant extensions and additions. They’re not a DA submission requirement but they sit directly in the chain of a well-managed development project.
Town planners work with rules. The planning scheme specifies what can be built, where it can sit on a site, how high it can go, how much of the site it can cover, and how it relates to neighbouring properties, the street and the broader environment.
Every one of those rules is applied to real-world site conditions. And the only reliable source of real-world site conditions is a survey.
When a planner assesses a DA, or prepares one for lodgement, they’re working from the information provided. If that information is inaccurate, the assessment is inaccurate. A proposal that appears to comply based on estimated levels or an outdated sketch may not actually comply once accurate data is applied. That can mean a refusal, a request for more information that stalls the application, or conditions of approval that require redesign.
Planners who work on complex sites, sloped land, infill development, character areas, flood-affected properties, know this from experience. The projects that move smoothly through the DA process are almost always the ones where accurate survey data was in hand before the planning work began, not chased down halfway through.
The relationship between a surveyor and a town planner is a practical one. The surveyor’s job is to capture what exists with precision. The planner’s job is to take that picture of existing conditions and map a proposal onto it that meets the planning scheme. Each relies on the other. A planner working from poor survey data is trying to solve a puzzle with the wrong pieces. A surveyor who understands what a planner needs will structure their output to make that assessment work as straightforward as possible.
At Survey My Block, we work alongside planners and designers regularly. We know what a DA submission needs, we know how contour data gets used in height calculations, and we know what level of detail makes a planner’s job easier versus what creates more questions. That working relationship matters, particularly on sites where the planning assessment is going to be scrutinised.
So, Do You Need a Survey Before Your DA?
For most residential and commercial DAs involving new structures, extensions, or changes to how land is used, yes. A detail and contour survey is the baseline. If your boundaries are uncertain or your setbacks are tight, add a boundary survey. If you’re on a sloped site, in a flood overlay, or dealing with a character home or heritage listing, accurate survey data isn’t optional, it’s the thing that holds the whole application together.
Get it done early. Brief your surveyor on what the project involves so the output is structured for what your planner and designer actually need. And treat it as an investment in the application, not an afterthought.
The cost of a survey is small relative to a DA delay, a redesign or a refusal. The projects that move well through the approval process are the ones where the groundwork was done properly at the start.
