UNDERGROUND UTILITY MAPPING
CHARTERED LAND SURVEYORS
High-standard utility detection to strict PAS 128 specifications
Malcolm Hughes delivers high-accuracy underground utility mapping to help you plan, design, and build with absolute confidence. Our PUMA-accredited surveys are carried out by highly experienced teams using advanced GPR and geospatial technology.
As one of the UK’s largest and fastest-growing geospatial survey companies, we deliver precision-driven underground utility mapping. Four decades of technical expertise ensures seamless project execution to support effective infrastructure throughout the UK and Ireland.
What is underground utility mapping?
Underground utility mapping is the comprehensive process of locating, identifying, and charting buried services and utility infrastructure beneath the ground surface. This includes electricity cables, gas pipes, water mains, telecommunications, fibre optics, and drainage systems.
Understanding what lies beneath the surface is critical for safe and efficient project planning. Striking a buried utility can result in major project delays and significant health and safety risks for on-site personnel.
At Malcolm Hughes, we combine industry expertise with advanced technology to deliver clear, practical insights that support safer, more informed decisions throughout excavation, design, and construction.
Related Case Studies
Utility Survey for Salford Active Travel
Discover how we delivered PAS 128‑compliant utility mapping and detailed topographical surveys for Salford’s Chapel Street Active Travel Scheme, helping the project finish four months ahead of schedule and within budget by reducing risks, enabling coordinated service diversions, and supporting efficient, safe delivery.
Subsurface Risk Mapping on Edinburgh Highway
Find out how we tackled hidden subsurface obstructions with high‑resolution GPR to support safer, more efficient resurfacing works for Edinburgh City Council.
PAS 128 surveys & PUMA accreditation
PAS 128 is the industry-recognised specification for underground utility verification and location in the UK. It serves as the definitive benchmark for how underground utility mapping surveys should be classified.
We deliver fully PAS 128 compliant surveys, giving you absolute confidence in the traceability and technical accuracy of our data. From high-detail surveys in congested urban areas to targeted investigations on greenfield sites, our work is carried out to a defined methodology.
We are also proud to be PUMA-accredited. This is an independent, TSA-led scheme that explicitly verifies a company’s ability to deliver underground utility mapping surveys to PAS 128 standards. Because our capabilities are regularly audited, you are guaranteed the consistent delivery of the highest standards in utility detection.
Tailored survey solutions
We adapt our methodologies to suit your specific site conditions and project outcomes, acting as a trusted partner throughout planning and delivery.
- Ground-Penetrating Radar (GPR) surveys
A non-destructive geophysical method that transmits radar pulses into the ground to image the subsurface. It successfully detects both metallic and non-metallic utilities (such as plastic pipes, fibre optics, and concrete ducts) as well as unmapped underground voids.
We regularly deploy high-resolution GPR across dense urban environments and complex infrastructure layouts to achieve critical risk reduction. A prime example of this sector expertise is our work in Edinburgh City Centre, where we utilised specialised GPR technology to tackle hidden subsurface obstructions, mapping more subsurface hazards than anticipated to support safer, more efficient resurfacing works.
- Drainage mapping and CCTV services
Accurately mapping gravity-fed utility systems requires specialised technology. We pair utility detection with CCTV camera surveys to assess the directional flow, connectivity, and structural integrity of foul and surface water drainage networks.
- Bespoke EV charging utility surveys
We offer specialised surveys tailored for EV charging point installations. We identify existing high-voltage capacity, grid connections, and potential underground obstructions to streamline your installation process.
Unrivalled sector expertise
With decades of hands-on experience navigating complex operational challenges, we are perfectly placed to provide an in-depth consultancy service for all forms of measured data across a diverse range of industries, including:
- Utilities & energy/renewables
- Roads & highways
- Railway infrastructure
- Government & public sector assets
- Aviation & airports
- Engineering infrastructure
- Commercial & residential property
- Ports & harbours
Your trusted geospatial partner
Choosing Malcolm Hughes means partnering with an industry leader dedicated to protecting your project timelines and budgets.
- We have been industry professionals for over 50 years, with our longevity validated by the industry’s most rigorous accreditations.
- We are a trusted partner chosen by National Highways, Network Rail, and the Environment Agency, among many others.
- With our deep pool of experience and a nationwide team of experts, we provide consultant-level advice to ensure your project succeeds.
- Our strategically located offices across the UK mean we can mobilise experienced underground utility mapping teams quickly.
What our clients say
“We engaged Malcolm Hughes to provide sub-surface mapping surveys on a large area of Edinburgh City Centre. The team were quick to mobilise to site and highly adaptable to the environment. They fulfilled the specification to a high standard and in a timely manner, with survey results clearly indicating more sub surface hazards than we had anticipated – definitely a high value service that we’ll undoubtedly be utilising again with Malcolm Hughes.”
Ritchie Clift, Associate Engineer CEng MICE IntPE (UK), AtkinsRealis
“Despite speaking to many survey companies synonymous and specialising in this type of work, Malcolm Hughes presented unique solutions to overcome the challenges and upon contract award their staff were professional, reliable, highly competent and a valued team member throughout the duration of their contract. I would have no hesitation in using Malcolm Hughes in the future.”
John Edelsten B.Sc. IEng MICE, Project Manager, BAM Nuttall Limited
Frequently asked questions
What is the difference between a standard utility trace and a PAS 128 survey?
A basic utility trace usually only identifies individual, easily accessible services using basic equipment. A PAS 128 compliant underground utility mapping survey adheres to strict British Standards Institution (BSI) frameworks. It provides a standardised data verification process divided into four specific quality levels:
- PAS 128 Quality Level D: The foundational step for project risk reduction. We conduct a thorough desk-based study, collating, reviewing, and analysing existing utility asset owners’ records to identify known infrastructure within your site boundary.
- PAS 128 Quality Level C: Our surveyors cross-reference the desktop utility records against visible surface features on-site (such as manhole covers, valve boxes, and marker posts)validating historical records with real-world observations.
- PAS 128 Quality Level B: The core of underground utility mapping. We utilise advanced geophysical techniques (specifically Electromagnetic Locators (EML) and Ground Penetrating Radar (GPR)) to detect and trace the precise ground position and depth of buried services, offering maximum certainty.
- PAS 128 Quality Level A: Utilities are physically exposed and verified via vacuum excavation or trial hole techniques, providing absolute validation of their exact position.
PAS 128 surveys gives engineers, developers, and project managers a transparent and legally robust account of exactly how accurate the location data is.
Can Ground Penetrating Radar (GPR) detect plastic and non-metallic pipes?
Yes. Unlike traditional Electromagnetic Locators (EML), which require a metallic conductor or trace wire to send a signal, Ground Penetrating Radar (GPR) detects anomalies based on changes in the subsurface soil matrix. This allows our surveyors to successfully locate non-metallic features, including plastic water pipes, clay drainage ducts, fibre optic lines, and concrete structures, as well as unmapped underground voids.
How deep can underground utility mapping equipment accurately detect services?
The depth capability depends on ground conditions and soil composition, but under standard UK conditions, our advanced equipment can accurately detect buried infrastructure at the following depths:
- Electromagnetic Locators (EML): Can reliably trace metallic utilities up to a depth of roughly four to five metres.
- Ground Penetrating Radar (GPR): Typically achieves an optimal depth range of two to three metres in standard soils. High-frequency antennas offer pinpoint resolution for shallow utilities, while lower frequency options can penetrate deeper, though high moisture or dense clay soils can occasionally attenuate the radar waves and reduce depth penetration.
Why do I need a topographical survey alongside my utility mapping survey?
An underground utility mapping survey tells you where the utilities are relative to themselves, but without a topographical survey, those services exist in a vacuum. By digitally overlaying utility detection data onto an accurate 3D map of permanent physical surface features (such as building footprints, kerbs, fence lines, and existing manholes), we provide absolute spatial context.
