New Zealand’s urban and suburban areas are threaded with thousands of kilometres of underground infrastructure. Telecommunications cables, gas mains, water and wastewater pipes, fibre-optic networks, and stormwater systems run beneath streets, driveways, and building sites, often sitting less than half a metre below the surface. For contractors and builders, this is the hidden risk that precedes almost every ground-breaking project.
Striking one of these services can mean electrocution, gas leaks, service outages affecting entire streets, flooding, and potentially serious financial and reputational damage. The good news is that it is almost entirely preventable with a methodical pre-dig process.
The Legal and Practical First Step: Before You Dig NZ
Before any excavation, site preparation, drilling, or even fencing work begins, contractors are required to locate underground services. Before You Dig New Zealand (BYD NZ) is the established first point of contact. By submitting a request through BYD NZ, contractors receive detailed site plans from utility providers, typically within a few working days.
These plans should be treated as a starting point, not a definitive map. They show approximate service locations based on records, which may not reflect every installation, modification, or deviation from design. Using them without additional verification is a common source of incidents.
Confirming Exact Locations Before Breaking Ground
Once BYD NZ plans are received, the next step is to physically mark service corridors on-site using paint or pegs. From there, safe digging techniques such as hand-digging or potholing should be used to confirm exact depths and positions before any mechanical excavation begins near marked routes.
Documentation matters too. Responses from BYD NZ and any site-specific risk assessments should be retained in the site safety file throughout the project.
Common Mistakes That Lead to Incidents
Most underground service strikes share a common thread: someone skipped or shortened the verification process. Frequent errors include:
- Assuming older plans are still accurate when infrastructure may have been added or re-routed
- Relying on visual inspection of the ground rather than confirmed service locations
- Bypassing the BYD NZ process to save time at the start of a job
- Failing to re-check service locations after design changes that shift excavation areas
- Excavating near marked corridors without hand-digging to confirm exact positions
If Something Is Struck
Despite best practice, incidents can still occur. If underground infrastructure is struck, the response is straightforward: stop work immediately, secure the area, do not touch exposed cables or pipes, and contact emergency services and the relevant utility provider without delay.
Building a Dig-Safe Culture on Site
Preventing underground service strikes is as much a cultural issue as a procedural one. Including underground service checks in site inductions and weekly toolbox talks reinforces the importance of the process for every worker on site, not just supervisors. Discussing near-misses openly helps crews understand what is at stake, and creates an environment where following the process is the norm rather than the exception.
The financial and safety consequences of a strike more than justify the time taken to do it properly. A few days waiting for plans and an hour of hand-digging is a small investment against the alternative.
Explore more health and safety guidance for New Zealand construction sites, or find contractors and industry professionals committed to safe working practice.
