Knowing exactly where your property boundary sits before you start any excavation is essential — cross the line and you could face legal disputes, damage a neighbour's land, or even undermine a shared fence or structure. In New Zealand, boundary information is held in official records and can be accessed by homeowners, but for anything more than a rough check, you'll want a licensed cadastral surveyor to peg the boundary accurately.
Why Getting Your Boundary Right Matters
Property boundaries in New Zealand are defined by the legal survey plan (also called a survey diagram or deposited plan) lodged with Land Information New Zealand (LINZ). These plans are the legal record of where your title begins and ends. If you dig, build, or excavate past your boundary — even by a few centimetres — you could:
- Encroach on a neighbour's land (a legal trespass)
- Damage underground services that cross the boundary
- Invalidate your building consent
- Face costly remediation or court action
This is especially important when excavating for retaining walls, foundations, driveways, or drainage works, all of which may also require a building consent under the NZ Building Code. Always check with your local council before digging.
Step 1 – Check Your Title and Survey Plan
Start by obtaining your certificate of title and the associated survey plan (deposited plan). You can search these through LINZ (Land Information New Zealand) via their Landonline public search tool. Your title will reference the deposited plan number (e.g. DP 12345), which shows the dimensions and shape of your lot.
Read the plan carefully — it will show boundary lengths in metres and bearing angles. However, interpreting a survey plan accurately takes practice, and the plan alone won't tell you exactly where those lines fall on the ground.
Step 2 – Look for Existing Survey Pegs
Survey pegs (also called boundary pegs or survey marks) are physical markers placed by a licensed cadastral surveyor when the land was originally subdivided. They are typically:
- Iron pins or rods driven into the ground, sometimes with a plastic cap
- Located at the corners of your section
- Sometimes buried just below the surface, especially in older sections
Use a metal detector to help locate buried pegs — this is a perfectly legal and practical DIY step. Check corners first, then work along fence lines. Be aware that pegs can be disturbed or removed over time, so a found peg should be verified, not just assumed correct.
Important: It is illegal under the Survey Act 1986 to intentionally disturb or remove a survey peg. If you accidentally uncover one, leave it in place.
Step 3 – Use a Licensed Cadastral Surveyor
If you cannot locate pegs, or if the stakes are high (major excavation, retaining walls, boundary fences), hire a licensed cadastral surveyor to re-peg your boundary. This is the only legally reliable method. A cadastral surveyor will:
- Search the official LINZ records
- Use GPS and total station equipment to calculate exact boundary positions
- Place new survey pegs at the corners
- Provide a report you can rely on legally
You can find licensed cadastral surveyors through the New Zealand Institute of Surveyors or by searching on tradedirectory.co.nz for local professionals in your area.
Step 4 – Check for Underground Services
Before any digging begins, locating your boundary is only part of the picture. You must also identify underground services — water, gas, electricity, telecommunications, and stormwater lines — which may run near or across your boundary.
Contact Dial Before You Dig (0800 248 344 or beforeudig.co.nz) at least two working days before excavating. This free service notifies relevant utility owners who will then provide plans showing their assets. WorkSafe NZ requires that underground services are identified before any excavation — striking a gas or power line can be fatal.
Step 5 – Check Council Rules and Consent Requirements
Even once you know your boundary, check your district plan and NZ Building Code requirements before digging. Excavation near boundaries can affect:
- Setback rules — how close you can build or excavate to the boundary
- Retaining wall height — walls over a certain height typically require building consent
- Earthworks rules — many councils have rules about the volume of soil you can move without consent
The MBIE Building Performance website has clear guidance on when building consent is required. Schedule 1 of the Building Act lists exemptions, but always confirm with your local council — rules vary by district.
Step 6 – Talk to Your Neighbours
If your excavation is close to a shared boundary, it's good practice (and sometimes legally required) to notify your neighbours. Excavation near a boundary can affect the stability of their land and structures. Under the NZ common law principle of lateral support, you have a duty not to remove support from neighbouring land. For significant excavations, your council may require a geotechnical assessment.
When to Call a Professional
Always engage a licensed cadastral surveyor before any significant excavation near a boundary — this is non-negotiable for retaining walls, foundations, or any work within a metre or two of the boundary line. For excavation involving gas lines, only a licensed gasfitter registered with the Plumbers Gasfitters & Drainlayers Board may work on gas infrastructure. For electrical cables, contact your lines company — never attempt to expose or work near live cables yourself. A qualified excavator operator found on tradedirectory.co.nz can also advise on safe digging practices and help you avoid costly mistakes.
Licensed Building Practitioner (LBP)
