Non-destructive hydro excavation to safely expose and verify buried utilities.
DBYD compliant. Tight access locations serviced across greater Sydney.
Potholing is a targeted excavation method used to physically expose and visually confirm the location, depth and condition of buried utilities before any major ground work begins. Unlike electromagnetic locating or ground-penetrating radar, which estimate the horizontal position of services from the surface, potholing creates a small physical opening in the ground so that the asset can be seen, measured and photographed.
At Pro Expose Hydro Vacs, we perform potholing using hydro excavation technology. High-pressure water is directed into the soil to break it apart, while a powerful industrial vacuum simultaneously extracts the loosened material into a spoil tank mounted on our vac truck. Because no mechanical tools contact the ground, there is virtually zero risk of striking or damaging live gas, electrical, water or telecommunications lines buried beneath the surface.
Potholing is considered the gold standard for underground service verification across Sydney. It satisfies the duty-of-care requirements set out by Safe Work NSW, utility asset owners and principal contractors, and it is the only method that provides absolute confirmation of a service's exact depth and alignment before excavation, boring, piling or trenching begins on site.
Our potholing crews safely expose every category of buried infrastructure found across Sydney residential and civil sites.
A systematic approach that ensures every buried asset is safely identified and documented before ground work proceeds.
Potholing is not optional on most Sydney worksites. Any time mechanical plant, augers, rock hammers or excavator buckets will penetrate the ground near known services, visual confirmation of those assets is required before work can proceed. Here are the most common scenarios where our potholing crews are called in:
Under NSW legislation, anyone planning to excavate must first lodge a free enquiry with Dial Before You Dig (DBYD) to obtain plans showing all registered underground assets at the worksite. These plans reveal the approximate alignment of gas, water, sewer, electrical and telecommunications services, but they do not show depth or exact position. That is where potholing becomes essential.
Pro Expose Hydro Vacs works hand-in-hand with your DBYD plans. We cross-reference the utility responses with on-site electromagnetic locating and then pothole each identified service to provide visual confirmation of its true depth and alignment. This process satisfies the due diligence requirements of Safe Work NSW, asset owners such as Sydney Water, Jemena, Ausgrid, Telstra and NBN Co, and principal contractors managing Sydney construction and civil projects.
Failing to pothole near live services can result in utility strikes, costly repairs, project shutdowns and serious injury. Our non-destructive digging approach eliminates that risk entirely.
Purpose-built for the tight access sites and congested utility corridors that define Sydney suburbs.
Potholing is targeted small-area excavation to physically expose a buried service. The goal is simple: confirm with your own eyes exactly where the asset sits, what it is made of, what condition it is in and how deep it runs. No more guessing from a paper plan. No more relying on an electromagnetic estimate. The asset is in front of you, photographed, measured.
There is a real difference between locating and potholing. Service locating uses electromagnetic detection or ground penetrating radar (GPR) from the surface to give an estimated horizontal position and rough depth. Locating is fast and useful for marking-out, but it has hard limits. EM gets confused near other metal. GPR gets noisy in wet clay or near reinforced concrete. Depth readings are estimates, often off by 100 to 300 mm. For a service locating mark you cannot trust to dig hard against, potholing is the next step.
Potholing physically confirms what the locator predicted. You see the actual asset. You measure the actual depth. You photograph the actual condition. That is what your design engineer needs, what your asset owner requires before they will sign off the trench, and what your insurer will ask for if a service strike happens later.
Potholing is commonly required by asset owners on Sydney sites: civil contractors before any deep mechanical excavation, crews trenching near gas mains, fibre optic crews working under telco asset rules, water authority maintenance teams, and anyone working near Ausgrid or Endeavour Energy high-voltage cables. The list is broader than people realise. Under AS 5488 and most asset-owner permits, plus standard WorkCover NSW guidance, visual confirmation is the expected practice before invasive ground work near known services.
The standard Sydney workflow is DBYD-then-pothole-then-dig. You lodge a Dial Before You Dig enquiry, get the registered asset plans back, mark out the surface, then potholing physically verifies each marked service before mechanical excavation starts. Skip the potholing step and you are excavating on a paper estimate, which is how service strikes happen.
These four terms get used interchangeably on Sydney sites but they are not the same thing. Here is what each one technically means:
| Term | What It Means |
|---|---|
| Potholing | Small targeted excavation to expose a single service for visual confirmation. The output is a hole, a photo and a depth measurement. |
| Non-destructive digging (NDD) | The umbrella method category. Any digging that does not damage utilities. Includes hydro vacuum, air vacuum and careful hand-dig. |
| Hydro excavation | The technique using high-pressure water plus industrial vacuum (versus air vacuum excavation, which uses compressed air instead of water). |
| Vacuum excavation | The broader process category. Includes both hydro and air variants. The vacuum truck is the equipment, the technique inside it varies. |
In practice, all four terms overlap. Potholing is usually done using hydro excavation, which is a form of vacuum excavation, which is a form of NDD. So a "hydro vac potholing job" and an "NDD service exposure" can describe the same physical activity. Where it matters: in formal contract scopes, asset-owner permits or insurance documents, the more specific term wins. If a permit asks for "non-destructive digging", potholing using hydro vac satisfies it. If an asset-owner specifies "hydro excavation only" (some gas authorities do, because air vac is not approved on their assets), only the water-based technique counts. We use the term the document uses, then deliver the right method underneath. Read more on non-destructive digging and hydro excavation for the technical detail on each.
Problem: NBN and telco sub-contractors often need fibre runs trenched along Inner West footpaths where DBYD plans show existing telco assets crossing the proposed trench at unknown depths. Visual confirmation is required before bringing in mechanical trenching equipment.
Approach: We hydro vac pothole each crossing point, expose the existing service, photograph and depth-measure, then mark the safe trench corridor.
Outcome: Typical result is a documented service map that satisfies the asset owner's permit conditions and lets the trenching crew work to known clearances rather than estimated depths.
Problem: Homeowners replacing concrete driveways often have a Jemena medium-pressure gas main running under the driveway alignment at an estimated depth from the DBYD plan. Mechanical breakout without confirmation creates a strike risk.
Approach: We hydro vac pothole at two points along the gas main route, expose the steel main, photograph at true depth, and brief the demolition contractor with measured clearances before any saw cutting begins.
Outcome: Typical result is a controlled saw cut depth that clears the gas main with documented margin. No strike, no Jemena callout, no stop-work order.
Problem: Bondi and Paddington heritage terraces typically have 900mm side gate access and no rear lane. Builders extending the rear of the property need water and stormwater services exposed for footing design. Most full-size vac operators decline these jobs because their trucks cannot reach the rear yard.
Approach: Our mini vac fits through 900mm gates. We park the truck street-side, run the hose 15-20 metres through the side gate to the rear, then pothole each service point. Unmapped drains are common in pre-1980 terraces and we find them before the builder does.
Outcome: Typical result is a verified service layout that lets the builder redesign footing alignment around unmapped infrastructure that would otherwise have been struck. Job completed in a single shift on standard hourly rate.
Potholing is a non-destructive excavation technique that uses high-pressure water and industrial vacuum suction to dig a small, targeted hole and expose buried utilities. The water loosens the soil while the vacuum removes the slurry into a spoil tank, leaving underground services like gas, water and power lines visible and undamaged. It is the safest method for verifying the exact position and depth of buried assets before construction begins.
Potholing is required whenever mechanical excavation, drilling, boring or piling is planned near known or suspected underground services. Sydney councils, utility providers and Safe Work NSW guidelines mandate that buried assets must be visually confirmed before any invasive ground work. This includes new home builds, road and footpath upgrades, civil infrastructure projects and any work within the zone of influence of existing utilities.
Potholing can safely expose all types of buried utilities including natural gas mains, water and sewer pipes, high and low voltage electrical cables, fibre optic and copper telecommunications lines, NBN conduits, and stormwater drainage infrastructure. Pro Expose Hydro Vacs regularly exposes assets owned by Jemena, Sydney Water, Ausgrid, Endeavour Energy, Telstra and NBN Co across greater Sydney.
Potholing in Sydney is typically charged at an hourly rate that includes the vac truck, operator, water and spoil disposal. The total cost depends on the number of potholes required, site access, soil conditions and depth of services. Pro Expose Hydro Vacs provides upfront quotes with no hidden fees. Call 0438 498 274 for a free estimate based on your specific job.
Service locating uses electromagnetic equipment or ground-penetrating radar to detect the approximate horizontal position of buried utilities from the surface. Potholing goes a step further by physically excavating a small hole to visually confirm the exact depth, material type and condition of the service. Most projects require both: locating first to mark approximate positions, then potholing to verify before construction proceeds.
Yes. Before any potholing or excavation work in Sydney, a Dial Before You Dig (DBYD) enquiry is legally required to identify all registered underground assets at the site. DBYD plans are free and typically returned within two business days. Pro Expose Hydro Vacs works with your DBYD plans to accurately pothole and confirm each service on site. We can guide you through the DBYD process if needed.
Not exactly, though the terms get used as if they were. NDD (non-destructive digging) is the umbrella method category. Potholing is one specific application of NDD: small targeted holes to expose services for visual confirmation. NDD also covers larger excavations, trenching, and any digging that protects existing utilities. So all potholing is NDD, but not all NDD is potholing. On a Sydney site, if a contractor says "we need NDD here", they often mean potholing, but they could mean a full NDD trenching program. Always check the scope before pricing.
Potholing is exact. You see the asset, measure the depth with a tape, photograph it. Ground penetrating radar is an estimate. GPR depth readings can be off by 100 to 300 mm depending on soil moisture, asset material and surface conditions. GPR is also defeated by reinforced concrete and is unreliable in saturated clay (common in Western Sydney after rain). For marking-out, GPR is fast and useful. For "is this thing 600 mm deep or 900 mm deep before I cut a footing here", only potholing gives the answer with confidence. Most Sydney civil contractors use GPR or EM locating to map first, then pothole at the critical points.
For typical Sydney service exposure, potholing depths sit between 0.5 m and 2 m, which covers almost all residential and commercial buried utilities. The water lance can cut deeper, but the vacuum extraction range is what sets the practical limit on the day. Standard hydro vac equipment reaches 3 to 4 m comfortably with the right hose extensions. Anything deeper becomes a specialised civil setup. If you need to expose a service known to be 4 m+ down, mention it when you book so we can bring the right hose configuration. Most jobs do not need this.
Yes. A lot of our work is residential potholing: homeowners replacing driveways, builders extending the rear of a heritage terrace, plumbers exposing a buried sewer junction, electricians confirming a service mains run before a switchboard upgrade. The mini vac truck is built for residential access through 900 mm side gates. Surface reinstatement on lawn, paving or driveway concrete is part of the job. We leave the site cleaner than we found it. If your residential job needs underground services exposed before any digging, potholing is the right call.
It depends on where the fence line runs. If the post holes are away from any registered underground service, hand-dig or auger is fine. If the line crosses or runs near gas, water, telco or electrical assets shown on the DBYD plan, potholing the post locations first is the safe call. Auger blades have hit gas mains plenty of times in Sydney over the years. The cost of one pothole is much less than the cost of a service strike, a Jemena callout, and a stop-work order. For boundary fences along the street frontage where lateral connections (water, sewer) cross, potholing each post location is genuinely worth the hour of vac truck time.
Different scope, different equipment, different price. Potholing is a small targeted excavation, usually 300 to 600 mm wide, dug to expose one specific underground service. Trenching is a long continuous excavation, typically 200 to 400 mm wide and several metres long, dug to lay or expose a run of pipe or cable. You can do both with the hydro vac (NDD trenching) or with mechanical equipment. Most Sydney workflows do potholing first to confirm what is below, then trench between the potholed points using whichever method the asset owner permits. If you are not sure which one your job needs, send the scope through and we will tell you.
Pro Expose Hydro Vacs provides potholing and underground service exposure across all Sydney metropolitan suburbs and surrounding regions.
Contact Pro Expose Hydro Vacs today for a free potholing quote. Send a photo of your site and suburb for the fastest response.
Operating from our Merrylands depot, we cover all of Sydney, including Parramatta, Inner West, Eastern Suburbs, North Shore, Bondi, and Merrylands. Same-day dispatch available.