GPR in the field
GPR technician identifying a septic tank and leach field.

Subterra utilizes the Utility Scan Ground Penetrating Radar (GPR) unit from industry-leader Geophysical Survey Systems, Inc. (GSSI).

GPR is used to locate non-metallic, non-conductive utilities and objects including:

-Water lines, concrete structures

-Sewer lines, septic tanks, leach fields

-Storm water & drainage, empty pipes

-Underground Storage Tanks

-Concrete Scanning

-Geologic Investigations (bedrock and water table mapping)

-Archeological Investigations (old foundations, gravesites, burials)

-Forensic & Security Investigations


Click here to watch a short video about GPR.


GPR has become a valuable tool in the locating industry in recent years. In the past, there were many utilities that are made of non-conductive materials and were considered to be untraceable. GPR has given us the ability to “see” many of these utilities that were previously difficult to locate. GPR is often used in combination with other locating equipment to account for all likely and possible utilities at a site. In certain situations, GPR can be the best method for locating utilities and other known or suspected buried objects when other locating equipment is unable to do so. GPR is a non-invasive, non-destructive method for locating and mapping underground utilities and buried objects.


Click Here to learn how GPR works.


GPR Images:

Top of concrete septic tank.
Leach field pipes.



Top of UST (perpendicular).
Top of UST (lengthwise).













3D GPR Survey

Most of the time when we’re using the GPR for utility locating purposes, a 2D “linescan” is all that is required. With this technique, we’re identifying and marking targets in real-time as we go across the ground surface. Sometimes, though, 2D doesn’t give us enough information to be conclusive. This is usually the case when we’re searching for possible Underground Storage Tanks (USTs).

The search for USTs usually requires the use of a 3D survey in order to be conclusive. This technique entails collecting a series of 2D scans in both directions of a precisely laid out grid. Once all of the data is collected, it is processed with specialized software that creates a simulated 3D view of the target. The 3D survey allows us to get a better look at the shape and size of the target and to separate it out from any other utilities or background clutter.

UST 3D Grid Survey


Who Is Using Our GPR Services?

– Residential Homeowners (Click here for a Homeowner Info Sheet)

– Commercial Businesses

– Industrial Facilities

– Government Agencies

– Municipalities

– General Contractors, Excavators, Builders, Electricians, Plumbers

-Designers, Planners, Engineers, Environmental Consultants

– And many more; no job is too big or too small for us.