Frequently Asked Questions | NJ Ground Penetrating Radar & Utility Locating

What Is a Locate?

Utility locating is the process of identifying and labeling underground public utility mains. A locate is the name given to the detection, marking and reporting of buried utility services on a job-site or work location.

Utility lines are detected using the transmission of radio-frequency signals applied to the line and perceived by a portable rf. receiver scanning over the ground above the location of the line. Another method of locating and identifying subsurface utilities is Ground Penetrating Radar (GPR).

The detected signal is then marked on the surface of the ground using temporary marking paint, stakes, or flags in order to indicate the horizontal position of the line.

This process is called a “locate”. It may be applied to both public and private utility lines.

What Is The Difference Between a PUBLIC and a PRIVATE Locate?

A “public” locate is a locate provided by a utility company for the services and utility lines they own and maintain, whether they are on public or private property. Utility lines are located to the “dissemination point” or “point of service” by the Utility Company, and each Utility Company may define exactly at what point their service ends and the private service owned and maintained by the property owner begins.

“Private” locates can begin at that point to detect and mark the location of services owned by the property owner. Typical dissemination points include the meter location, a service valve, a transformer, or even the property line. Contact the specific Utility Company for more information.


What Utility Lines Are Typically Considered “Private?”

Utility lines typically considered private include, but are not limited to the following:

  • Water lines inside property boundaries.
  • Sanitary and Storm Sewer line inside property boundaries.
  • Gas lines beyond the gas meter, such as those feeding outbuildings, BBQ’s, pools, generators, machinery, etc.
  • Power lines beyond the meter, or the site transformer or substation, such as the main service lines into a building from such a point, or sub-services to outbuildings, sub-panels, etc.
  • Electrical lines for signage, parking lot lighting, walkway lighting, gates, pumps islands, machinery, block-heater plugs, etc.
  • Telecommunication lines (phone, cable, internet, and network) beyond the telecom room or dissemination point, such as internal property networks, closed-circuit TV cameras, alarm systems, communication, and phone systems, etc.
  • Irrigation lines, though many are plastic only, and not locatable. Wiring to valves and solenoids can be located.
  • Air lines and hydraulic lines for equipment and machinery.
  • Fuel and product lines from AST’s and UST’s, including gasoline, diesel, heating oil, waste oil, etc.
  • Fill and vent lines for Underground storage tanks.
  • Fiber optic lines for onsite communications. Note: fiber optic lines themselves are not locatable, but they may have a tracer or sheath that is.
  • Any other service or utility line that is owned, installed and maintained by the property owner as opposed to an outside third party Utility Company.

Why Should I Get a Private Utility To Locate?

It is in the best interests of the excavator to retain a private utility locator regardless of the information provided by Utility Companies or property owners to ensure the safety of the crews engaged in the excavation and to prevent damage to personnel, property, and utility lines.

Excavators are required by law to exercise due diligence in this regard. Damages can cost time, money and lives.

How Close Can I Dig To a Utility Line Marking?

No mechanical excavation is to take place within 3 feet horizontally of any utility line markings (flags, paint, or stakes, etc.). “Scratching the surface” above utility lines, boring beneath an uncovered line without hand-excavating to full crossing depth, or digging up to a line with mechanical means is NOT acceptable.  Depths of lines may vary and must be determined by hand-digging.

Multiple lines in a common trench, or positioned above each other may interfere with accurate locating, and appear as only one line.  Adjacent utility lines may distort the electromagnetic fields required for accurately locating and offset the marks.  For all of these reasons and more, contractors MUST respect the three-foot rule.

How Deep Is The Utility Line?

The installation of Utility lines is usually regulated by local building codes, electrical codes, etc.  However, site conditions vary, and lines are seldom installed exactly as they should be.

While Pipe & Cable Locate Equipment is capable of measuring the depth of connected lines, depth measurements are notoriously erroneous and can be affected drastically be things like soil density, surface material, and even humidity.  Therefore, the depths of utility lines are seldom given on locating reports and are to be taken cautiously at best.

Reported depths do not relieve the contractor from the obligation to excavate within 3 feet horizontally of marked utility lines by hand, without mechanical aid.  This cannot be stressed enough.

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