Subsurface Utility Engineering (SUE) is a branch of engineering that involves utility design and relocation services.  The most critical component of providing Support for a SUE project involves designating and locating underground utilities. This aspect of the design phase of building and construction helps manage the risks associated with unexpected encounters with underground utilities. Obtaining the most accurate mapping and information on the existing utilities through Master Locators' Subsurface Utility Engineering support service allows engineers to design the most efficient system.

Levels of Subsurface Utility Engineering

Master Locators uses several different methods to perform these SUE support services, depending on the different quality levels of data necessary for the project. According to the ASCE Standard 38-02, which is used across the A/E/C industry. There are four different quality levels of data:

  • Level A - Underground Utility Locating (Test Hole): This is the highest confidence level of utility locating, in that each test hole allows for visual confirmation that guarantees the horizontal and vertical location of the utility. This is accomplished using nondestructive vacuum excavation to safely expose, measure and map utilities.
  • Level B - Utility Designation: This level of data is collected using geophysical equipment operated from the surface to designate the locations of underground utilities. Utilities are marked out and recorded on a map with plan documents.
  • Level C - Visible Surface Feature Utility Survey: Level C data maps out utility surface features by surveying the area and plotting what’s visible above ground. It is used to supplement Level B data and update or correct as needed.
  • Level D - Record Research/Data Collection: This level of data is derived from records research or oral history. It gives an idea of how congested the area may be, but does not provide specific and accurate detail as to where the paths of the utilities are located.  Any existing conditions plan which does have a utility level documented on record is automatically considered Level D data by the ASCE 38-02 standard.

Multiple Tools and Approaches

Master Locators has an extensive history of using multiple tools to retrieve the necessary level of data specific to a subsurface engineering project:

  • Our state of the art ground penetrating radar equipment (GPR) is used to locate metallic and non-metallic underground utilities, including: Fiber Optic, PVC, HDPE, and more.
  • Our electromagnetic induction tools help to locate metallic underground utilities not detectable by GPR.
  • After the existing utilities are designated, the next step is to verify their locations at all points of interest, and whenever the new proposed utility route crosses an existing utility. Our Hydro and Air vacuum excavation trucks are used to expose utilities for collecting accurate depth information critical for designated utility crossings. Vacuum excavation virtually eliminates the risk of damaging underground utilities and is especially useful in areas of high utility congestion or in confined spaces.

Why Worry about Subsurface Utility Engineering?

Subsurface Utility Engineering Support is vital in the planning and design phase of a project, playing a crucial role in preventing interference between projects and underground features. Implementing subsurface engineering early in the design phase of a project virtually eliminates costs associated with project delays and change orders due to unexpected encounters with underground utilities. It is most helpful when implemented in the beginning stages of a project as a preventative measure and to ensure the safety of all workers.


What Quality Level am I required to use on my project?

The utility standard does not require a certain level of utility data, however, best practices suggest obtaining at least Level B data on any project that will require subsurface penetrations and Level A data on any designed utility crossing.

Can excavation be performed under a body of water?

Master Locators cannot perform excavation under a body of water. If the water is diverted or removed, Master Locators can perform excavation in this area, even if the ground is saturated. If groundwater is encountered, Master Locators can excavate approximately 1'-2' through the groundwater before the water level overcomes the excavation and work must stop.