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Underground Service Locating, Detection & Mapping

Know exactly what’s below before you dig

Get a free quoteCall 0800 779 588

Since 2015Own locators, hydro-vac & diggersAuckland · Franklin · North Waikato

Leak detection and service detection jobs can start from $300 +GST. Every job is different, so call 0800 779 588 and we’ll talk through your situation and give you an estimate. Commercial work: talk to us about your site.

Call 0800 779 588

Start here

So you need to dig — and you don’t want to hit anything.

A new driveway, a fence line, a subdivision, a trench for power or water. Somewhere under there are cables and pipes, and the plans — if there are any — are rarely right.

We locate and mark what’s actually there, physically confirm it where it matters, and hand you a map you can build from. If you then need it dug, we do that too.

Here’s what we can do

  1. Pre-Dig InvestigationStart here for any job that breaks ground — a full check and mark-out of everything buried on the site.Learn more
  2. Ground Penetrating Radar (GPR)Add this when there are plastic pipes, tanks, voids or anything a standard locator can’t pick up.Learn more
  3. Hydro Excavation & PotholingChoose this to physically expose a service and confirm its exact depth before machines go near it.Learn more
  4. Survey & GPS MappingChoose this when you need the records — survey-grade GPS positions and shapefiles for designers, engineers and consents.Learn more
  5. CCTV Drain SurveysSonde-equipped drain cameras find blockages, breaks and the exact line and depth of a pipe.Learn more

Not sure what you need?

Most people aren’t — and you don’t have to be. Tell us what you’re seeing and we’ll tell you what it needs, before anyone turns up with a digger. People usually describe one of these:

  • Building, fencing, landscaping or trenching
  • A site with no reliable service plans
  • Working near power, gas or fibre
  • Needing as-built records for a consent
Call 0800 779 588 Send us the details

Mon–Fri 7am–5pm · based at Waiau Pa, South Auckland

What we locate

Every buried service — whichever one you’re worried about

Whichever service above you book, these are the utilities we trace, mark out on the ground and map.

  • Power

    Live and de-energised cables traced with electromagnetic locators — the ones a strike makes dangerous.

  • Water

    Metal and plastic mains and laterals, by tracer wire, acoustic methods or GPR where locators can’t see.

  • Gas

    Steel and PE gas pipes traced with EMI or tracer-wire systems, so excavation never guesses near gas.

  • Comms

    Phone, data and fibre — the cheap pipe to cut and the expensive one to repair.

  • Drainage

    Stormwater and sewer traced with sonde-equipped CCTV, including depth, breaks and blockages.

A few jobs people ask for

Some of the things we get called about

Not a full list — just the requests that come up most. If yours isn’t here, it almost certainly still is something we do.

  • Homeowners · fencers

    Fence posts, a deck or a new driveway

    Small digs hit services too. A quick locate and mark-out before the auger or digger goes in.

  • Builders · homeowners

    Extension or new build

    Everything buried on the site located and mapped before foundations — and a record for the consent file.

  • Builders · electricians

    Cutting or coring a slab

    GPR scan of the concrete first, so the saw doesn’t find the conduit for you.

  • Developers · civil

    Subdivision or civil works

    Full site survey, GPS-mapped shapefiles, utility marking for crews, potholing on anything critical.

  • Commercial · rural

    Old site, no plans

    Factories, schools, farms with decades of unknown pipes and cables — located, traced and mapped properly for the first time.

  • Something else?

    If it’s underground and it carries power, water, gas or comms, there’s a good chance we do it. Describe the job and we’ll tell you straight.

    Call 0800 779 588 →

Why Utility Works

Finds it. Digs it. Fixes it.

Most locating companies hand you a map and leave. Most contractors dig first and hope. We do the whole job with one team.

One crew, start to finish

Locators, hydro-vac truck and diggers on the same team. The people who find it are the people who fix it — no second contractor, no re-marking.

Non-invasive first

Acoustic correlators, GPR, pipe tracing and potholing find the answer before anything is dug. We only open ground where we have to.

Local since 2015

Based at Waiau Pa — most of Franklin, South Auckland and North Waikato is under an hour away, and we know the ground and the councils.

Certified locators, done properly

Our locators hold NZ Certified Locator certification, so you get compliant methods, accurate marks and a survey plan of what went where — and the surface left so you’d never know we were there.

For civil, utility & development work

Underground Service Locating For Contractors And Asset Owners

The commercial side of the job — locating a whole site to a standard your health-and-safety plan and your principal will accept, with the data to prove it.

Pre-dig service location across the site

Every power, water, gas, comms and drainage service located and marked before a machine starts — the locate your H&S plan and consent conditions call for.

Subdivision & civil works

Locating across whole development sites so services get designed and dug around, not through — with GPS-mapped output for the design team.

Network operator & asset-owner locates

Locating and verifying buried assets for the councils, networks and bodies corporate who own them — then exposing or repairing them with the same crew.

How it goes

From your first call to a finished job

  1. Send us the site

    Address, what you’re planning, any plans you have. We’ll tell you which checks the job needs and when we can be there.

  2. We locate and mark

    Electromagnetic locating, GPR and CCTV/sonde trace every buried service; we paint and flag it on site and pothole anything critical.

  3. You get the map

    A marked-up plan or survey-grade GPS shapefile so your designer, digger operator or council has the record.

Let's discuss your underground project needs. Contact us today for a free, no-obligation quote.

Free, no-obligation quote · Mon–Fri 7am–5pm · Auckland, Franklin & North Waikato

Call us0800 779 588Get a free quote

A closer look

Still not sure which one? Here’s each in more depth.

Pre-Dig Investigation

Pre-Dig Investigation

Before any excavation we sweep the site with electromagnetic locators, trace live power, gas, water and comms, and paint and flag everything on the ground. Where plans exist we check them against what’s actually there — they’re often wrong.

It’s the baseline for any job that breaks ground, from a fence post to a subdivision, and the cheapest insurance against a strike that stops a project for weeks.

Good for

  • Any trenching, post holes or foundations
  • Builders, fencers, landscapers and drainlayers
  • Sites with no reliable service plans
  • Meeting health-and-safety obligations
Pre-Dig Investigation →Get a quote
Ground Penetrating Radar (GPR)

Ground Penetrating Radar (GPR)

Standard locators only find things that conduct — metal pipes and live cables. GPR sends radar into the ground and reads what bounces back, so it picks up plastic water and gas pipes, old tanks, voids, concrete and anything else a locator can’t see.

We use it alongside electromagnetic locating on complex or older sites, and for scanning slabs before coring or cutting.

Good for

  • Plastic pipes and non-conductive services
  • Scanning concrete before cutting or coring
  • Old sites with unknown buried structures
  • Voids, tanks and septic systems
Ground Penetrating Radar (GPR) →Get a quote
Hydro Excavation & Potholing

Hydro Excavation & Potholing

Locating tells you roughly where and how deep. Potholing proves it: pressurised water loosens the ground and a vacuum lifts it away, exposing the actual pipe or cable without a blade going near it. We then know its exact position and depth before the digger arrives.

The same truck does slot trenching, daylighting around poles and pits, and keeps a trench clear when groundwater is flowing in.

Good for

  • Confirming depth before mechanical excavation
  • Working close to power, gas or fibre
  • Trenching in congested service corridors
  • Sites where a strike is unacceptable
Hydro Excavation & Potholing →Get a quote
Survey & GPS Mapping

Survey & GPS Mapping

Marks on the ground wash off. GPS mapping records every service we locate to survey grade and delivers it as shapefiles or CAD-ready data — so designers, engineers and the council have a record that lasts.

Typically combined with a pre-dig investigation; also used to produce as-builts of what we’ve installed.

Good for

  • Design and consent documentation
  • As-built records after installation
  • Developers and civil contractors
  • Asset registers for large sites
Survey & GPS Mapping →Get a quote

Google reviews

What customers say

5.0 on Google →
  • “Prompt service & fair pricing. Tony and his team — sharp eye for detail and out of the box problem solving paired with a high standard of workmanship.”

    Richard La Trobe · Google · October 2026

  • “Really happy with the work to install our underground services. Highly recommend.”

    Sarah Walworth · Google · October 2026

  • “The only company we trust… reliable, cost effective, and honest service from A to Z. 100% confidence in this company.”

    Darrel Assink · Google · September 2026

Detection & Mapping Specialists

Our Projects

Services Detection & Mapping in Tuakau

Tuakau, North Waikato

Services Detection & Mapping in Tuakau

A local power network provider in Pukekohe needed expert service detection and mapping. With multiple high-voltage cables traced and marked out, duct and drainage tracing, water mains tracing and multiple communications cables in the vicinity, the project required our specialist services and expertise.

Read the case study
Golf Course Pond Leak Detection in Auckland

Auckland

Golf Course Pond Leak Detection in Auckland

Lined ponds pose many challenges once underground loss occurs. Utility Works was contracted to assist with the locating of pond leaks at a large Auckland golf course ahead of the dry summer months, when the irrigation system relied on the water supply. The process involved underwater diving and installation of pipe air bags to block the balance pipe and separate the two ponds, enabling accurate loss calculation, followed by GPR and IR works to determine likely areas of loss. The ponds were pumped out to enable locating of the defects for repair. We also assisted with the irrigation flow and isolation testing during the process.

Read the case study

Worth a read first

Guides & advice

1–3 of 6

Before You Dig in NZ: What beforeUdig Gives You and What It Doesn't

Before You Dig in NZ: What beforeUdig Gives You and What It Doesn't

Everyone planning to dig in New Zealand is told to lodge a beforeUdig enquiry first, and they should. But the plans that come back are a starting point, not a mark-out. This guide explains what beforeUdig actually provides, where its plans fall short on real sites across Auckland and the Waikato, what professional service locating adds, and the sequence that keeps you, your crew and your budget out of trouble.

Read the guide
Pre-Dig Investigation in Auckland: Why It's the Most Important Step Before You Excavate

Pre-Dig Investigation in Auckland: Why It's the Most Important Step Before You Excavate

Every excavation project starts the same way — with ground that looks empty on the surface but is often anything but underneath.

Read the guide
How Accurate Is Ground Penetrating Radar in New Zealand Soil Conditions?

How Accurate Is Ground Penetrating Radar in New Zealand Soil Conditions?

Ground penetrating radar is the tool people ask for when they want to see everything under a site, and it is the one most often oversold. How accurate it is depends almost entirely on what the ground is made of, and New Zealand ground varies from scoria that radar loves to saturated clay and peat that swallow the signal within half a metre. This guide sets out what GPR can realistically find in the soils around Auckland, Franklin, the Waikato and the Hauraki Plains, how accurate the positions and depths are, and how it fits with the other locating methods.

Read the guide

FAQ'S

What is underground service detection and mapping?
Underground service detection uses specialised equipment to locate buried utilities such as power cables, water pipes, gas lines, and telecom ducts. Certified service locators employ ground penetrating radar (GPR, electromagnetic locators, and tracer cables or Sondes to detect both conductive and non-conductive objects. The positions are marked on site and recorded so you or your contractor knows precisely where it is safe to dig.
Why should I arrange utility detection and mapping before I dig or build?
Any excavation – from a new build or subdivision to a small home project in Auckland – risks striking hidden services. Damaging a power or gas line can cause outages, safety hazards and legal liabilities. Professional utility detection identifies buried networks, allowing you to plan trenching safely and meet health‑and‑safety requirements.
What technologies do you use?
Utility Works combines several methods to ensure precise results. Ground‑penetrating radar sends radar pulses into the ground to detect non‑conductive objects like plastic pipes, voids and tanks; electromagnetic locators trace live or de‑energised power and data cables; specialised tracing systems locate gas and water pipes. We also use sonar‑equipped CCTV cameras for drainage tracing and hydro‑vacuum excavation to verify depths.
Will you provide a service map or digital files?
Yes. Upon request, we supply a map of all services within your property. Our survey‑grade GPS mapping produces digital shape files that can be integrated into CAD or GIS platforms for design and compliance purposes
Do I need to contact Council or use BeforeUdig?
Before beginning any excavation, you should conduct a pre-dig investigation. Councils and asset owners often require you to obtain plans and engage certified locators to mark utilities before you dig. Using professional detection services helps you comply with council regulations and avoid fines for damaging underground assets. Utility Works provides certified pre-dig investigations and plans.
Who benefits from underground service detection?
The service is invaluable for property developers, civil contractors, councils and schools in Auckland upgrading infrastructure, and farmers or rural property owners adding new power or water lines. Whether the project is a large-scale infrastructure upgrade or a single residential connection, accurate underground mapping saves time, money and stress.
How quickly can you respond?
Utility Works prioritises urgent issues across Auckland. Our local crews aim to respond quickly to burst water mains, power faults or leak‑detection emergencies. The duration of a detection job depends on the site’s size and complexity, but we work efficiently to provide results promptly so your project can move ahead.

Ready when you are.

Tell us what you’re seeing or what you’re planning. You’ll get a straight answer, a free quote and one crew that does the whole job.

Call us0800 779 588Email usinfo@utilityworks.co.nzGet a free quote

Mon–Fri 7am–5pm · Waiau Pa, South Auckland · Auckland, Franklin & North Waikato