Utility Locating Services Explained

A labyrinth of utility lines and other obstructions lie hidden under our feet.

It's important to know where every pipe, conduit, and line is located before you break ground. Utility locating is the process of identifying and marking the location of underground utility lines, pipes, and cables such as gas lines, water pipes, sewer pipes, electric lines, and telecom lines for phone, cable, and internet services. It's vital to locate these items prior to breaking ground to help prevent construction and excavation workers from accidentally damaging or disrupting these underground utility lines or pipes, which can result in service outages, property damage, injury, or even death.

Utility locating also helps save time and money by identifying potential conflicts with utility lines before construction or excavation work begins.


States provide a public utility locating service (811) free to anyone excavating to prevent public utility strikes. The contractor on the project is required by law to call 811 to avoid subsurface damage.

811 services go by different names depending on what state in which you reside. Some common names for this service are Call Before You Dig, Dig Alert, Digline, and One Call.

A utility findings map.
Private utility locating services such as GPRS can determine the line depth, the location of abandoned lines, and more.

The most important thing to note is that 811 services are limited to public utilities; they do not account for private utilities that may also be run through your job site. Further, 811 marks the location of the line, but does not provide a depth measurement.

Once a line connects into the infrastructure of a private facility, it is no longer considered a public utility. This is where it is vital to employ a private utility locating service such as GPRS. We can determine line depth, the location of abandoned lines, and more, and we provide you with high-quality digital maps, markings and a complimentary PDF and KMZ file to compliment the services of 811 and give you a comprehensive picture of the built world on your site.


As mentioned above, utility locating prevents costly and potentially dangerous subsurface damage. A single utility strike costs, on average, $56,000 to repair. But that's just money. The real threat of subsurface damage is to the health and safety of your workers and the people in the community in which you are working.

You don't want to be responsible for a gas line explosion, or a disruption of services to a hospital. These catastrophes are avoidable with proper utility locating.


GPRS' Project Managers primarily utilize ground penetrating radar (GPR) and electromagnetic (EM) locators to find buried utilities. 

GPR is the most efficient and accurate tool for modern utility locating. This non-destructive detection and imaging method involves sending a radio signal into a structure and then reading the "bounce" of those radio waves off any material they encounter. This creates a reading that displays those bounces as hyperbolas. An experienced GPR technician, such as GPRS' Project Managers, interprets this reading to determine the type of material located. 

EM locating is a complimentary technology to GPR. An electromagnetic signal is either sent through an underground utility line by a transmitter, or the receiver searches for an existing electromagnetic signal in an active line.

The data from these various technologies is compiled by an experienced technician to create an accurate map of the underground infrastructure on your property.

A screenshot from SiteMap.
GPRS’ Project Managers primarily utilize ground penetrating radar (GPR) and electromagnetic (EM) locators to find buried utilities. And when we conduct a utility locate of your site, you get a complimentary personal subscription to SiteMap, our revolutionary facility management platform, so you can easily view, manipulate, and collaborate around your facility information.


Utility locating deliverables are not universal between utility locating companies. It's important to know what products and services are offered by a utility locating company you are considering hiring.


Clients often receive field markings in the form of paint, pin flags, stakes, or any other method they request. GPRS trains our Project Managers to ensure that all the field markings they apply are clear and easy to understand. Additionally, each GPRS Project Manager uploads their findings into SiteMap® where our clients can securely view and collaborate around their facility information.


PDF files are images that visually communicate what utilities are located where. Think of a PDF file as a physical paper map that you can view on a computer or mobile device. KMZ files, on the other hand, are tagged with geolocated points that indicate specific utilities, pipes, lines, and other features. GPRS offers a complimentary PDF and KMZ map with every utility locating project.


CAD files can be 2D or 3D renderings of a space. CAD drawings allow contractors, engineers, and owners to develop or update as-built drawings. Clients use these files for preplanning, to avoid utilities, or to document the history of their site on various CAD and GIS systems.

The Future of Utility Locating

While any look towards the future of an industry is primarily speculation, we must look ahead to what’s on the horizon.

We’ve seen an incredible technological jump in the last 20 years, and now we’re seeing a convergence of those technologies. Due to battery capacity and compactness innovation, drones have become a more viable solution for unmanned and affordable aircraft. GPRS can detect subsurface voids, leaks, and utilities from hundreds of feet in the air using thermographic and magnetic imagery. Additionally, image capturing drones can provide excellent building façade imagery and documentation that would previously have proved impossible to produce.

Legislation is also a significant factor to consider when speculating what the future of utility locating and marking look like. Because of the massive amounts of damages and the severe safety risk posed when striking utilities, it’s possible that hiring a private utility locator will be a legal mandate. SUE services may also become mandatory for specific excavation or construction processes to mitigate the damage.

While water and sewer lines are under the ground, it’s common for electrical and communication lines to be strung from towers and poles above. These lines may be undergrounded in the future to prevent damages and safety hazards. 

A worker conducts a utilty locate in a field.
Utility locating technologies continue to advance. With the cloud becoming a more significant part of our everyday lives, we can predict that databases will one day be the primary storage of utility lines and location data.

Additionally, with the cloud becoming a more significant part of our everyday lives, we can predict that databases will one day be the primary storage of utility lines and location data. Currently, data is siloed and challenging to access between areas and companies. Eventually, a centralized service could store and collect utility location data. This data will most likely be acquired and managed by private utility locators through a shared database or individual methods.

These databases would be valuable storehouses of information that could benefit facility owners and managers in perpetuity.

While no one can perfectly predict what the future will hold for utilities and underground utility locating, it is a certainty that methods will evolve as we continue to advance technologically.