This GBCA Toolbox Talk was developed in collaboration with the Pennsylvania One Call System. This toolbox talk discusses utility line locate marks, and the responsibilities of contractors and workers with checking for and maintaining marks.

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Click below to download the Toolbox Talk as a handout (includes Sign-In Sheet).




Identify and Mark Utility Lines Before Digging

Before any digging or demolition project, construction workers need to check for utility lines. While this is most important for excavation contractors, all workers should be knowledgeable of these markers. This toolbox talk, created in a collaboration between GBCA and Pennsylvania 811, explains utility line locate markers and excavators’ responsibilities in helping maintain them.

Under Pennsylvania’s Underground Utility Line Protection Act (UULPA), the facility owner is required to post a Positive Response to all notifications through the One Call system. Excavators are expected to check to see how the facility owners respond to their dig notification before they even leave their office. Notifications must be made at least three business days before digging may lawfully start, giving facility owners time to send locators to mark any underground utility lines.

See the GBCA Safety Toolbox Talk, “Safe Digging on Construction Sites,” for information about excavators’ responsibilities with regards to digging.

Excavators should compare the list of utilities that were notified on the dig notification to the list of responses received from the facilities owner the morning of the lawful start date. Excavators are
responsible for notifying the One Call center by using Pennsylvania 811 Positive Response System with any locate related issues prior to the start of excavation. Excavators may be contacted by
locators if there are any issues with dig notifications.


Locate Markers

All utilities in the vicinity of a dig site are required to be located and marked. Correct marks have four components:

  1. Facility Owner’s name
  2. Color code indicating the type of utility
  3. Size of the line or facility
  4. Material of the line or facility

The color code is a nationally-used system set by the American Public Works Association (APWA), required by the UULPA, and part of the best practices set by the Common Ground Alliance (CGA).


The UULPA requires that locators physically mark, stake, or locate the position of underground lines at the work site location within 18” horizontally from the outside wall of the line. This location is known as the tolerance zone.

Powered equipment SHOULD NOT be used within the tolerance zone to protect buried utility lines.


Respecting the Marks: Excavator Responsibilities

Excavators need to provide the facility owner locator with the exact and specific location of where digging will take place. The UULPA requires that if an exact and specific location cannot be
described in the dig notification, then the excavation area should be marked in white. Marking the excavation area in white, however, is the recommended best practice, even if an exact location is known.

The excavator is responsible for protecting and preserving a facility owner’s stakes, markings, and other designations until they are no longer required for safe excavation or demolition work.

If there are unmarked or incorrectly marked utility lines, or if marks have been compromised or eliminated during work, the excavator needs to contact the facility owner and PA One Call System
to get the locate marks refreshed.

In the Pennsylvania 811 Positive Response System, there are two forms to address marks: Update Tickets and Renotify Tickets.

UPDATE Ticket:

  • Should be used when work has not started within the original lawful start date window. Can be used when work is in progress and lines need to be re-marked.
  • Has UPDATE in the banner section. The remarks will indicate the serial number of the ticket being updated.
  • Assigns a new Serial Number and references the original Serial Number.
  • Resets the Lawful Start Dates to be 3-10 business days from the creation of the UPDATE ticket.
  • Indicates if the excavator needs the site to be remarked.
  • Is delivered to all members based on the drawn notification area.


  • Should be used to report an unmarked or mismarked line, or when the caller disagrees with a response made by a member.
  • Has RENOTIFY in the banner section.
  • Adds a version number to the existing serial number but does not change the serial number.
  • Retains the original Lawful Start Dates and no information on the ticket can be modified.
  • Is delivered only to the members requested by the caller.
  • Includes the reason the caller requested the re-notify.


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