The Essential Guide to
Potholing in Construction
Potholing is the process of excavating small, precise holes to visually confirm the exact location of underground utilities before a major dig begins. If you’re planning any significant excavation work in Australia, this guide covers everything you need to know — from the mechanics of the process to your compliance obligations in 2026.
Overview
What Is Potholing and Why Do Builders Use It?
The term refers to a targeted excavation technique used to safely expose underground services: water mains, gas lines, electrical conduits, telecommunications cables, and stormwater infrastructure. Rather than relying solely on utility plans — which can be inaccurate, outdated, or simply wrong — potholing lets your team physically see what’s down there.
In Australia’s construction and civil works sector, potholing has become a non-negotiable first step before any significant groundwork begins. The risks of skipping it aren’t theoretical. Striking an energised electrical cable, a high-pressure gas main, or a critical fibre optic line can shut down an entire project — and in the worst cases, it can be fatal.
Pressurised water breaks up the soil while a vacuum simultaneously extracts the slurry, exposing underground assets without any physical contact — faster, safer, and far more accurate than traditional mechanical excavation.
Step-by-step
How the Potholing Process Works
Understanding the steps helps you plan smarter and brief your crew properly before mobilising.
Obtain Utility Records
Request current Dial Before You Dig (DBYD) plans for the site to establish a baseline of known services.
Mark the Site
Flag suspected locations of underground utilities based on DBYD data and any available as-built drawings.
Set Up the Hydrovac Unit
Position the vacuum excavation truck within operational reach of the target area.
Excavate the Pothole
Use pressurised water to break up soil directly above the suspected utility, then vacuum it clear to expose the pipe or cable.
Visually Verify and Measure
Confirm the service type, depth, condition, and precise horizontal location on-site.
Document All Findings
Record everything with photographs, GPS coordinates, and written notes before backfilling.
Backfill and Compact
Restore the pothole with appropriate fill material and compact to the required standard.
The Reality
Why Utility Plans Aren’t Enough on Their Own
A common assumption on site is that DBYD plans provide sufficient certainty before digging. They don’t — and experienced project managers know this.
Utility records in Australia are maintained by dozens of different asset owners across federal, state, and local government bodies, as well as private networks. Data gaps, outdated as-built drawings, and unregistered legacy infrastructure are widespread. Research has consistently shown that a significant proportion of underground assets are either inaccurately mapped or entirely unrecorded.
This is particularly relevant on older residential and industrial sites, where decades of subdivision, redevelopment, and network upgrades have created layered, poorly documented service corridors. Even on newer sites, construction tolerances mean a service could be 300–500mm away from where the plan says it is.
Risk Management
The True Cost of Skipping Potholing
The short-term saving of skipping potholing is almost never worth it. Here’s what a single unplanned utility strike can actually cost your project.
Emergency Repair Costs
Repairing a severed water main or telecoms cable can run into tens of thousands of dollars, often billed directly to the contractor.
Project Downtime
A single strike can halt a site for days or weeks while network owners carry out inspections and repairs.
Regulatory Penalties
Under WHS legislation, failure to manage underground service risks can attract significant fines and enforcement action.
Insurance Complications
Claims arising from utility strikes are frequently contested when proper pre-excavation investigation wasn’t carried out.
Reputation Damage
Repeat incidents can result in loss of contractor accreditation with major clients and government bodies.
Cost of professional potholing vs. the risk
Regulatory Framework
Australian Compliance Requirements
Australia’s approach to underground utility safety is governed by a combination of WHS legislation, the AS/NZS 2885 series for pipelines, and state-specific codes of practice for construction work near underground assets.
Safe Work Australia’s Code of Practice for Excavation Work requires that all underground services be identified before any excavation begins.
Most major infrastructure clients — including state road authorities, utilities, and local councils — now mandate potholing as part of their project specifications.
For government-funded civil projects in 2026, potholing is either a legal requirement, a contractual obligation, or both.
The AS/NZS 2885 pipeline series sets specific standards for excavation works in proximity to high-pressure pipelines and critical infrastructure.
Compliance isn’t just good practice — it’s how you protect your licence to operate. Duty holders who fail to adequately manage underground service risks face significant fines and enforcement action under state and territory WHS legislation.
Frequently Asked Questions
Common Questions Answered
Potholing is a targeted, non-destructive method designed specifically to expose underground utilities at precise locations. Standard mechanical excavation uses buckets or blades that can easily damage buried services. Potholing uses pressurised water and vacuum suction to remove soil without any physical contact with the asset being exposed.
Hydrovac potholing can typically reach depths of three to five metres, which covers the vast majority of buried utilities encountered on Australian construction sites. Greater depths are achievable with specialised equipment and the right site conditions.
While specific requirements vary by state and project type, Safe Work Australia’s Code of Practice for Excavation Work requires that all underground services be identified before excavation begins. For most commercial and civil projects, potholing is either a legal requirement, a contractual obligation, or both.
A single pothole typically takes 30 minutes to two hours to complete, depending on soil type, depth, and site access. A project requiring multiple potholes across a large corridor can usually be completed within one to two days with a properly equipped hydrovac crew.
Ready to Start with Certainty?
Contact Hydrovac Pty Limited to discuss your site requirements and get a potholing assessment scheduled before your excavation begins.