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Underground Utility Locating

Underground Utility Investigations & Locating

Quality of Underground Utility Information is Key

C Below offers professional underground utility locating and mapping services throughout the South West. Our highly experienced technicians utilize the most advanced equipment in the industry to gather information for your project. Accurate information is vital in planning and can prevent costly delays from damages caused by cutting, coring, drilling, or digging in areas congested by unseen hazards in concrete, masonry, and underground. The tools we use and our approach will be tailored to the quality level of information you require.

Quality levels may be considered degrees of risk or how much information is needed to design or construct a project adequately. Plans typically contain disclaimers as to the accuracy of the utility information. The use of quality levels allows project owners to decide what level of information they need to manage the project’s risk level appropriately. Data can be provided in a pull box, electrical reports, potholing reports, underground mapping, 3D modeling, or surface markings.

There are four recognized quality levels of underground utility information ranging from Quality Level A (the highest level) to Quality Level D (the lowest level).

Quality Level A

The highest level of accuracy and involves the full use of the subsurface utility investigation method. It provides information for the precise plan and profile mapping of underground utilities through the nondestructive exposure of underground utilities and also provides the type, size, condition, material, and other characteristics of underground features.

Quality Level B

This involves the application of appropriate surface geophysical methods to determine the existence and horizontal position of virtually all utilities within the project limits. It addresses problems caused by inaccurate utility records, abandoned or unrecorded facilities, and lost references. Decisions regarding the location of storm drainage systems, footers, foundations, and other design features can be made to successfully avoid conflicts with existing utilities. Slight adjustments in design can produce substantial cost savings by eliminating utility relocations.

Quality Level C

This involves surveying visible utility facilities (e.g., manholes, valve boxes, etc.) and correlating this information with existing utility records (QL-D information). When using this information, it is not unusual to find that many underground utilities have been either omitted or erroneously plotted. Its usefulness, therefore, is primarily on rural projects where utilities are not prevalent or are not too expensive to repair or relocate.

Quality Level D

This is the most basic level of information for utility locations. It comes solely from existing utility records or verbal recollections, both typically unreliable sources. It may provide an overall “feel” for the congestion of utilities but is often highly limited in terms of comprehensiveness and accuracy. Thus, QL-D is useful primarily for project planning and route selection activities.


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Electromagnetic locating is often the most common and cost effective method for locating utilities. It is often the first step in a comprehensive investigation that may employ more than one method. We use a combination of many different tools to electronically locate utilities. There are four common methods electromagnetic locating.

Method 1

This direct connect method involves the technician directly connecting a transmitter to the line. A signal is sent down the utility or tracer wire buried with the utility and located with a receiver from above the surface. This is ideal for electrical, communication, and gas lines.

Method 2

Induction involves sending a signal through the surface to the utility when you cannot directly connect to it for various reasons. The utility then transmits this signal picked up by a receiver above the surface in the same manner as the Direct Connect method.

Method 3

Sonde locating involves inserting a locatable transmitter into a utility or conduit to be located by a receiver above the surface. Some of the tools we use that have locatable sondes in them are crawler cameras, push cameras, and ramrods. This method is often used for storm drains, waste lines, and empty conduits.

Method 4

Passive locating is a method where a receiver is used to pick up a naturally produced electromagnetic field emitting from a buried utility.

When utilities are located, our technicians use industry standard colors to mark them directly on the surface. Water based marking paint is used when permitted. When paint is not permitted in cases like finished decorative surfaces or high traffic customer areas, we can use chalk, wax or other marking materials. Flags and whiskers are also used in areas such as grass or dirt when paint markings will not last.

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Whether you have a project in the works or are still in the planning stages, let our team know how we can be of service. Take a moment to request a free quote for our utility investigation services.