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PAS 128 Survey


Compliant Utility Detection & Mapping

PAS 128:2022 is the most up-to-date specification for underground utility detection. The purpose of the PAS 128 specification is to set out the accuracy to which survey data is captured.


The quality expected from the data and the confidence in the information is highlighted. Where it is appropriate to specify a PAS 128 survey, there are benefits for the client, the practitioner and the general public.


The specification covers:


  • The project planning and scoping process

  • The classification system for quality levels. This system is based on the survey category type, the location accuracy, the need for post-processing and the level of supporting data.

  • Desktop utility records search

  • Detection

  • Verification

  • Location

  • Deliverables

As a result, PAS 128 provides a robust procedure for delivering quality utility surveys in the UK. There are four survey quality levels which the client can specify: A through to D. Each level focuses on the degree of precision that must be adhered to for the utility survey to be PAS 128 compliant. What's more, a survey area may be subdivided so that various and appropriate survey levels can be undertaken in different regions of the site.

The ability to segment areas of the survey area and apply different levels of PAS 128 to each, allows survey providers, such as SUMO to offer you a survey which meets your budget requirements as well as being compliant.

The following table shows the scope of each type of survey and an appreciation of the cost benefit.

Quality Level.

Scope upon which results are based

Relative accuracy obtained

Relative confidence level in results

Relative cost


Desktop utility records search





Site reconnaissance

Medium low

Medium low

Medium low


Detection with EML and GPR* 

Medium high

Medium high

Medium high


Verification using intrusive inspection** 




* A minimum of the two techniques of electro-magnetic location and ground probing radar is required for a PAS 128 compliant survey. The client specifies the methodology and intensity of the detection survey.** The verification survey specifies recording information available from manholes and intrusive excavation.


Example above of varying Levels of PAS 128 applied to a site area. Notice how the most intensive PAS 128 levels have been concentrated in areas where typically lots of utilities are found; such as around the buildings. A less intense PAS 128 quality level has been applied to the field areas. In doing this, you can still obtain sufficient survey data at a fraction of the cost.


The benefits of a SUMO PAS 128 Survey


  • Those involved in the design process, such as consulting engineers, benefit from the consistent, high-quality data obtained from utility surveys.

  • A quicker, straighter forward comparison of competing quotes, as all PAS 128 compliant quotations should rely on a similar methodology.

  • Construction professionals benefit from accurate survey data, which can be utilised for records of new works, facilities management, statutory document records and more.

  • Lower-risk of utility strikes.


What deliverables will I receive from SUMO?


The output of a SUMO PAS 128 Survey includes a colour coded CAD drawing showing all the detected utilities within the survey area, as well as the depths and quality levels shown. At SUMO, we can supply PAS 128 deliverables in a range of digital formats. Furthermore, SUMO is committed to offering its industry-leading knowledge in the form of FREE PAS 128 technical presentations aimed at improving your teams PAS 128 Survey knowledge and ensuring all site staff understand the deliverables given to them on site.


What are the benefits of a SUMO PAS 128 Survey?


Did you know that the PAS 128 Specification was part-funded by SUMO? Two technical directors of the SUMO Group were also appointed to the Drafting Panel and The Steering Group to assist with the writing of the PAS. The guiding role that SUMO played in the creation process means that we have an in-depth and unrivalled understanding of how PAS 128 works, allowing us to identify the best and most economical approach to applying PAS 128 certified survey options to your site.




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Chat through any requirements you need, including site survey, survey methodologies and detail requirements.

Utility Surveys


PAS 128 Utility Survey


Statutory Plan Collation


Utility Detection
& Mapping

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