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Commentary: ‘Call before you dig’ requirements aim for safety

Issue Date: November 25, 2015
By Karen Norene Mills
Locating line markers on a property represents an important initial step in assuring safety before excavation. But the markers only indicate approximate locations, so contacting a “one-call center” remains crucial to assure safety. The shapes, sizes and colors of the markers vary by utility owner and type of line.
Locating line markers on a property represents an important initial step in assuring safety before excavation. But the markers only indicate approximate locations, so contacting a “one-call center” remains crucial to assure safety. The shapes, sizes and colors of the markers vary by utility owner and type of line.
Karen Mills

Farmers and ranchers often serve as guardians for important utility infrastructure throughout California—both above and below the ground. The presence of overhead power lines or underground pipelines imposes obligations on farmers and ranchers—and can bring dangers, too. High-profile accidents caused by excavation projects have occurred in California in the past year.

You've likely seen advertisements in Ag Alert® and elsewhere, urging you to "Call Before You Dig," but you may be surprised by the rules and conditions behind the requirement to call 811.

The basics: If you're planning to excavate—defined as any operation in which earth, rock or other material in the ground is moved, removed or otherwise displaced in any way by tools, equipment or explosives—you must call a "one-call center." The centers for California are listed in an information box on this page. They administer a free service for receiving excavation reports and transmitting them to participating utilities with underground facilities in the excavation area, so they can mark the locations before the work begins.

There's a common understanding that activities such as irrigation system installation, deep ripping and orchard planting or removal trigger the need to call for marking. But the law also invokes a need to call before many other activities. As I learned this year while engaged in a legislative effort to update the current law, there are a number of reasons the calling requirements reach as far as they do, affecting safety, reliability and liability.

First: Natural gas transmission pipelines appear to pose the greatest risk of injury and damage. These are larger-diameter lines that operate at a higher pressure compared to distribution pipelines that deliver gas directly to the end user. But other types of infrastructure may be lying in wait underground, including oil pipelines, water lines, telecommunications lines or electrical lines, though underground electrical lines are not common in rural areas.

Second: Line markers and warning signs such as the ones pictured on this page only indicate the approximate location along the pipeline route. Markers will identify the materials carried underground, the name and contact information for the pipeline operator. But markers aren't indestructible, so just because you don't see a marker doesn't mean there's not a pipeline below.

Also, the markers provide only the general location of the infrastructure; the line may not follow a straight path between markers. Serious accidents have occurred because the markers didn't indicate a turn or angle in a line.

Most disconcerting is the fact that there is currently no mandate to maintain up-to-date information about the depth of underground lines. Although lines are installed to required depths, information on line depths is not refreshed on any regular basis.

Third: If there is an incident and the infrastructure is damaged, an excavator can face civil penalties of $10,000 for negligence, up to $50,000 for willful damage—in addition to any other remedies allowed by law. Such liability could occur if an excavator fails to comply with applicable laws and procedures, resulting in damage caused by that failure.

An important first step in managing the risk is to be aware of any markers on or near your property. You can also check websites that show locations of natural-gas transmission lines; examples are listed in the information box.

In addition, guidelines instruct these steps to take prior to excavation:

  • Mark the area to be excavated.
  • Call before you dig.
  • Wait the required time to allow the pipeline operator to mark the area.
  • Respect the marks.
  • Dig with care.

The directions you'll find online are largely directed at projects in urban areas, meaning you may have to make some interpretations on the best ways to apply them to agricultural projects. Utilities' outreach and education efforts have largely been focused on urban projects as well—but with increased attention on the safety of utility infrastructure has come increased attention on any activities around it.

The legislation to which I referred earlier, known as Senate Bill 119, ended up being vetoed. The bill included a requirement to gather necessary information in order to develop rules and requirements tailored to agricultural activities.

We don't yet know if future legislation will be introduced on this topic but regardless, it would be helpful to know about experiences farmers and ranchers face when conducting activities that prompt the need to "call before you dig." Have there been delays in pipeline operators' responses to requests for marking, or instances where the marking is incorrect? It would also help to know what types of lines are located on agricultural land, who provides information to you about underground pipelines, and whether you're receiving adequate information at on-site meetings about pipelines.

If you have information to share, let me know at In the meantime, please be safe.

(Karen Norene Mills is associate counsel and director of public utilities for the California Farm Bureau Federation.)


Where to find pipeline information

One-call centers

DigAlert: This organization covers Imperial, Inyo, Los Angeles, Orange, Riverside, San Bernardino, San Diego, Santa Barbara and Ventura counties.

USA North: This organization covers all other California counties not listed above.

Utility websites

Pacific Gas and Electric Co.:

Sacramento Municipal Utility District:

San Diego Gas and Electric Co.:

Southern California Gas Co.:

National Pipeline Safety website:

Information on how to mark infrastructure:

Permission for use is granted, however, credit must be made to the California Farm Bureau Federation when reprinting this item.

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