"Specialising in measured building, land & topographical surveys"

PAS128 Utility Surveys

Underground Utility Mapping GPR Surveys London. GPR Scanning Surveys UK, Utilities Surveyors London, Utility Tracing GPR Surveys, Utility Dectection Surveys London. GPR Surveys London.


Other titles for these surveys are PAS 128 GPR Surveys london, Utility Mapping Survey, Utility Surveys Surrey, sub Underground  surveys, Subtronic Surveys, Subsurface Surveys, Ground Penetrating Radar, utility mapping and Utility Surveys  Brighton.

London and south east based Underground Utility Surveyors specialising in GPR (Ground Penetrating Radar) surveys, Radio Detection Scanning, Drainage Surveys london and CCTV Drainage Condition Surveys london. All utility surveys are PAS-128 compliant.high detailed levels of PAS can be supplied. GPR Detection Surveys London. GPR Scanning Surveys.

 GPR utility survey at a petrol station site in Surrey using the DS2000 And Geomax GPS. 

Ground Penetrating Radar (GPR) Survey, Utility Surveying and Underground Utility survyeing in London and South UK. Utility Mapping Surveys to produce PAS 128 compliant plans.

Cadmap Utility GPR Surveying is a highly professional Underground Utility Surveyors, we specialise in the mapping of underground buried services accurately on the ground to show a full representation of existing services running through the potential development site or highways. GPR Scanning Surveys.

To locate the position of underground services and pipes is critical before any excavation work begins, to avoid a potential disaster. Undertaking an Underground services report gives you the vital information required to avoid such problems. All services located and mapping accurately plotted onto a CAD drawing using Leica Total stations and can be delivered in a variety of file formats.

Cadmap Underground Surveying London, professional staff operate the latest in Ground Penetrating Radar technology such as the IDS Detector Duo and Radio Detection RD8000.

Cadmap have a Utility surveying office in London, utility surveyors based in Brighton, GPR utility surveyors based in Southampton & Portsmouth and utility surveys in Surrey.

Utility GPR Detection Sureying using the Leica DS2000 GPR Survey in Brighton

What is a PAS128 Utility GPR Survey?

A PAS128 Utility Survey is a type of survey that aims to locate and map underground utility infrastructure within a specified area. PAS128 stands for Publicly Available Specification 128, which is a specification developed by the British Standards Institution (BSI) for the detection, verification, and location of underground utilities.

The purpose of a PAS128 Utility Survey is to provide accurate and reliable information about the location, depth, and nature of buried utility services, such as water pipes, gas lines, electric cables, telecommunications networks, drainage systems, and other underground assets. This information is essential for planning and design purposes, ensuring safe excavation, reducing the risk of utility strikes, and minimizing costly delays or disruptions during construction projects.

Borehole Excavation Clearance Surveys

Underground Utility Mapping Surveys London, Buried Utilities  GPR Surveyors Brighton. Underground Services Survey London.

Utility GPR Surveys London. Example in Camden - london 


A PAS128 Utility Survey typically involves the following steps:

  1. Desktop Study: A thorough review of available records, as-built drawings, historical maps, and utility plans is conducted to gather existing information about the potential presence and location of utilities within the survey area.

  2. Site Reconnaissance:  Cadmap Ltd Surveyors visit the site to visually identify visible utility features, such as manholes, valve covers, utility cabinets, and other surface-level indications of underground services. This helps in understanding the site context and identifying areas of potential utility presence.

  3. Geophysical Survey: Various geophysical techniques are used to detect and locate underground utilities. These techniques can include Ground Penetrating Radar (GPR), electromagnetic induction (EMI) or electromagnetic locating (EML) devices, magnetic methods, and other specialized tools. These instruments help identify anomalies and subsurface features that may indicate the presence of utilities.

Utility GPR Scanning Survey London tracing drainage in Surrey.

  1. Utility Verification: Once potential utility features are identified through geophysical methods, further investigation and verification are conducted to confirm the type, size, depth, and condition of the utilities. This may involve manual digging, potholing, or other non-destructive techniques to expose and visually inspect the utility assets.

  2. Data Processing and Reporting: The collected data from the PAS128 Utility Survey is processed, analyzed, and compiled into a comprehensive report or deliverables. The report provides detailed information about the identified utilities, including their location, depth, material, condition, and other relevant attributes.

  3. Undertaking a utility survey at a site in london.

Utility GPR Scanning Surveys for Utility Detection.

PAS 128 Utility Surveys are important for managing the risks associated with underground utilities, ensuring compliance with regulations, and promoting safe construction practices. They help project teams make informed decisions, plan excavation activities, and mitigate the potential risks of utility strikes, ultimately improving project efficiency and reducing costs.

Cadmap undertake GPR surveys London.  GPR Utility surveys in Brighton. GPR Utility Surveys in Southampton and Portsmouth. GPR Utility Surveys in Surrey.

What are the various levels of PAS 128 surveys?

The PAS 128 standard takes a hierarchical approach to survey types.

  • PAS 128 Level A – Underground utilities are observed, excavated or exposed.
  • PAS 128 Level B  Underground utilities are detected by geophysical techniques. For example, Electromagnetic Location (EML) survey and/or Ground Penetrating Radar (GPR).
  • PAS 128 Level C  Utility records are validated by visual inspection.
  • PAS 128 Level D  Desktop utility record search.

GPR survey London at a site in Westminster - london .

What is a GPR Survey?

A Cadmap GPR (Ground Penetrating Radar) survey is a geophysical surveying method that uses radar pulses to image and detect subsurface features and structures. It is commonly employed to investigate the composition, depth, and location of objects and subsurface anomalies within a wide range of materials, such as soil, rock, concrete, and pavement.

During a Cadmap GPR survey, a GPR system is used, which typically consists of a control unit and an antenna or a set of antennas. The antenna emits electromagnetic waves into the ground or other materials, and these waves bounce back or reflect off different subsurface features with varying properties. The antenna then receives these reflected waves, which are recorded and processed by the control unit.

The key principles of a GPR survey include:

  1. Radar Waves: GPR uses high-frequency radio waves, typically in the range of 10 MHz to 2.6 GHz, to penetrate the subsurface. The frequency selection depends on the specific survey objectives and the material being investigated.

Example of a service pipe detected from the Ground Penetrating Radar

  1. Reflections: When the radar waves encounter changes in subsurface materials or structures, such as interfaces between different materials, buried objects, or voids, they reflect back to the antenna. These reflections carry information about the depth, location, and characteristics of the subsurface features.

  2. Data Collection: The GPR system collects data by moving the antenna over the survey area in a systematic manner, typically along parallel lines or grids. The antenna emits radar pulses at regular intervals, and the received signals are recorded, forming a series of radar profiles or cross-sectional images of the subsurface.

  3. Data Interpretation: The recorded radar profiles are processed and analyzed to identify subsurface features and anomalies. By interpreting the amplitude and time-travel characteristics of the reflected signals, GPR data can help determine the presence of buried utilities, voids, rebar or reinforcement in concrete structures, changes in soil layers, or other subsurface features of interest.

GPR surveys are widely used in various applications, including:

  • Cadmap Utility Mapping: GPR can locate and map underground utilities, such as pipes, cables, and ducts.
  • Archaeology: GPR can help identify buried artifacts, structures, or archaeological features.
  • Geology and Geotechnical Investigations: GPR can provide information about subsurface stratigraphy, bedrock depth, and soil layer characteristics.
  • Structural Assessment: GPR can evaluate the condition of concrete structures, detect voids, and assess rebar or reinforcement integrity.
  • Environmental Studies: GPR can identify contaminants, monitor groundwater levels, and assess soil moisture content.

GPR surveys offer a non-destructive and efficient means of subsurface investigation, providing valuable insights for various industries and disciplines. However, it's important to note that interpretation of GPR data requires expertise and experience to accurately interpret and understand the subsurface conditions


Underground Utility Mapping Surveys London, Utility Surveyors Southampton. 

Cadmap Utility Surveying Methods.

Underground Utility Surveys London. 

Cadmap attend site equipped with an original land survey which shows the position of all service covers and site details. The surveyors traces underground cables, pipes using Radio Detection methods and ground penetrating radar equipment such as the RD8000 Detector, TX10 Genny and Leica DS2000 GPR radars. This information is then surveyed in either using a total station of GPS and then added to the existing survey, all connections, depths to pipes or cables direction are clearly presented on the drawings. All utility gpr surveys london are PAS128 utilty surveys compliant.

Drainage Survey Investigations UK.

Cadmap attend site equipped with an original land survey which shows the position and the level of manhole covers. Manhole covers are lifted in a safe and secure manor to ensure no danger is at risk to the public. Invert readings are measured, direction of flows are established and pipe sizes noted along with sewer construction, either foul or surface. This information is then added to the existing survey, all connections, invert levels and direction of flows are clearly presented on the drawings. Drain Survey London.

The above picture is a utility gpr survey we carried out in London on a major junction. 

Terms and Conditions for Utility/GPR Survey

Cadmap Ltd will endeavour to locate all buried services or sought features using a combination of electromagnetic detection and ground penetrating radar methods. We operate only within the industry wide limitations of these types of technologies. As such we cannot guarantee to include certain services/features in our survey. Where services or features cannot be located on site this will be recorded and record information will be annotated onto the site plans where available. Depth information on all services will be provided where available, but cannot be guaranteed. Utility Surveyors Hampshire and Southampton.

Specifically concerning GPR, on site factors such as concrete reinforcing bars, made up/rubble filled ground construction, high metal content in ground, water saturated areas, surface obstacles on site/uneven ground can all affect the quality of GPR data and ability to carry out a full survey. Surveys are compliant with PAS128 standards and practices.


Services we include

  • Electric supply cables to street lighting/other accessible powered structures
  • Low voltage electric cables 240v and higher
  • High voltage electric cables
  • Telecoms/Communications cables
  • Fibre optic cables
  • Drainage pipework where accessible from manhole chambers or other drainage features
  • Water pipes 63mm diameter and over
  • Gas pipes 63mm diameter and over
  • Fuel pipes 63mm diameter and over
  • Heating pipes
  • Underground service ducting
  • Specified radar locatable features (designated at time of enquiry)

Services we don’t include

  • Cut off, abandoned or disused utilities
  • Designation of a utility as live or dead
  • Individual service connections to properties without direct access
  • Drainage without available access points for a transmitter probe
  • Internal utilities (unless previously agreed)
  • Information within areas unsafe for working
  • Confined space entry into manhole chambers
  • Information for manholes found to be “unable to lift”

To View the RICS specification Measured Surveys of Land, Buildings and Utilities, 3rd edition click Here

Underground Utility Surveys in Brighton. 

GPR Surveyors London. Underground Utilities GPR survey based in Surrey office.

Cadmap Limited Office Locations:


  • Cadmap Land, Building and Utility Drainage Surveyors -Werks Central,15-17 Middle Street, Brighton, BN1 1AL 
  • Cadmap Land, Building and Utility Drainage Surveyors -Director General's House, 15 Rockstone Place, Southampton, Hampshire, SO15 2EP 
  • Cadmap Land, Building and Utility Drainage Surveyors -Unit 131 Dunsfold Park, Dunsfold, Cranleigh, Surrey, GU6 8TB


  • Cadmap Land, Building and Utility Drainage Surveyors - Office 9, Dalton House, 60 Windsor Ave, Merton, London SW19 
  • Cadmap Land, Building and Utility Drainage Surveyors -2 Woodberry Grove, North Finchley, London, N12 0DR 

Utility surveyors london, GPR surveys  London ground penetrating radar london , sumo surveys london, subtronic surveys london Surrey. Underground utility surveys london, 

London, Southampton, Brighton, Sussex, Surrey and surrounding area. https://www.drainage-surveys.co.uk/