Specification for Underground Utility Detection, Verification & Location

PAS 128 provides a robust methodology for delivering utility surveys in the UK. 

Construction  -   Real Estate  -  Civil  -  Utilities  -  Rail  -  Highways  -  Heritage  

British Standards Institution PAS 128, Specification for underground utility detection, verification and location is a publicly available specification document which allows the utility survey industry to deliver its services to a recognised level of accuracy.

Although it is aimed at the survey practitioner, we understand that our clients need a know how to specify a PAS 128 survey.

PAS 128 provides a robust methodology for delivering utility surveys in the UK. It focuses on levels of accuracy – referred to as Survey Category Types – that you can specify when requiring a PAS 128 compliant underground utility survey.

See: PAS128 Factsheets

PAS128 Compliant Surveys

Application of the PAS128 standard will mean more effective planning and safer execution of street works, civil works, ground works and utility based activities

  • Clarity in the service provided and methods employed.
  • Consistency in the approach to data capture.
  • Classification of the results and the confidence that can be associated with them.
  • Standardisation of the format of deliverables
  • Accountability for the work undertaken

Our Utility Detection and mapping services are offered at various levels of detail, which can be selected by you, depending on the site-specific survey requirements.

PAS128 Type D Survey

Type D

Desktop Utility Record Search: Underground utilities are identified through the collation and analysis of existing paper/online records. 

See PAS128 Factsheet

PAS128 Type C Survey

Type C

Site Reconnaissance
Existing records are supported and validated by the visual inspection of physical evidence observed during a site visit.

See PAS128 Factsheet

PAS128 Type B Survey

Type B

Underground utilities are observed and located through geophysical techniques to obtain a horizontal position and vertical position.

See PAS128 Factsheet

PAS128 Type A Survey

Type A

Underground utilities are observed and located in an inspection survey or manhole chamber or excavated and exposed.

See PAS128 Factsheet

Survey Types: PAS128 takes a hierarchical approach to the survey types used in recognition that different clients at different stages of an asset life cycle will require different levels of detail and confidence in the data provided.

This PAS defines four types of survey representing the different levels of effort required in obtaining information on the location of utilities, whereby the desktop utility records search requires the least effort and verification the most. 

A survey type D is a prerequisite for survey types C, B and A. Survey types A to C are independent of each  other.  For example, a detection survey can conform to PAS128 without the need to conduct a survey type C or A. 

Survey Planning: Typically a client and survey practitioner will meet to discuss the appropriate PAS128 Survey Category Type (D to A) and the methodologies to be used. Each project is different and there are many factors that may need to be discussed. The survey practitioner will advise on the best and most appropriate methods based on the information given.

Post Survey Meeting: Post survey, the survey practitioner will explain the accuracies achieved and any limiting factors. At this point it may be appropriate to suggest other methods of survey to achieve greater levels of accuracy in areas of concern/strategic project importance, a survey report will also be provided with any supporting evidence.

Survey Planning & Reporting

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Freephone:     0800 689 5315

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Our mission is to provide contractors, excavators, surveyors, engineers and designers the very best Information from Underground. 


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