PAS128 Surveys

A PAS128 Survey is an underground utility survey which detects, verifies, and locates all underground utilities.

PAS128 refers to a British Standards Institution (BSI) standard, originally introduced in 2014. The standard, which was revised in 2022, seeks to ensure that underground utility mapping surveys are completed with a greater degree of confidence and accuracy. The standard outlines the precise methodologies on how a utility survey should be undertaken, and the level of results that need to be issued within the report. By closely working to PAS128 standards, all underground utilities, such as electrical networks, sewer pipelines and telecommunication networks are mapped with a high degree of accuracy. There are four survey types with the PAS128 standard, with Type B being the most commonly instructed. If you are unsure what type is required, our team is on hand to discuss your project requirements and advise which type is required.


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Critical to many projects, which can range from the construction of a residential property to large-scale infrastructure projects, a PAS128 survey provides construction professionals with clarity on existing utilities and services within a given area prior to breaking ground. This enables more effective planning which, in turn, helps to mitigate potentially costly mistakes, project delays and damage to the existing utility services. Since the standard's introduction in 2014, Terrain Surveys are proud to have undertaken hundreds of high-quality PAS128 utility surveys for clients such as main contractors, consulting engineers and project managers throughout the UK. 


There are four Types of PAS128 Surveys, with Type B being the most commonly requested. For ease of reference, broadly speaking, the Types are outlined below;

  • PAS 128 Survey Category Type D refers to a 'Desktop Utility Records Search’ whereby an offsite survey is undertaken to identify known utility owners within a respective area, with the findings collated and presented in digital format.
  • PAS 128 Survey Category Type C Obtains information for Type D followed by a site visit to check the record information against existing site features, with the findings issued within an annotated plan or report.
  • PAS 128 Survey Category Type B: Is the most common form of PAS128 Survey we undertake; it obtains information for Type D or Type C, followed by a full on-site detection survey of all underground utilities, using Electromagnetic (EML) and Ground Penetrating Radar (GPR) techniques and methodologies.
  • PAS 128 Survey Category Type A: Finally, Type A refers to verification, whereby we would obtain deliverables for Type D, and where available, Type C and/or Type B. We would then agree with the client a place where excavation can take place to verify the exact locations of underground services.


Established in 2004, for nearly two decades Terrain Surveys have delivered thousands of utility surveys for clients throughout the UK and are proud to work to PAS128 standards. Many of our clients, which range from architects and garden designers to local authorities and multi-discipline firms view Terrain Surveys as their 'surveyor of choice' for both PAS128 surveys and other measured survey solutions.

We are proud members of The Survey Association (TSA) and are an Approved Development Partner at the Chartered Institution of Civil Engineering Surveyors (CICES) we are also, amongst other accreditations, pleased to be ISO:1009-accredited and hold Constructionline Gold membership.


We appreciate that a PAS128 survey is unique to each site and we therefore invite you to contact us and our team will carefully review your requirements. Once received, we will  provide you with a bespoke quotation which will be returned within 48-hours.

Whenever you instruct a PAS128 survey, an experienced surveyor is on-hand throughout the process to assist with any queries you may have regarding the survey. 

Our Head Office in Welwyn, Hertfordshire enables us to undertake PAS128 Surveys across London and the South East, and our regional offices in Birmingham, Bristol and Sussex ensure Terrain Surveys are well-placed to deliver PAS128 surveys and other measured survey solutions to clients throughout the UK.

If you have a project which could benefit from a PAS128 survey, please call us on 01438 841300 or email [email protected]. Alternatively, fill out the contact form and a member of our team will be in touch to discuss your requirements.


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If you would like to discuss a project please contact our team

Welwyn Office +44(0)1438 841300
[email protected]
Midlands Office +44(0)1788 877262
[email protected]

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