Avoiding Underground Utilities

Doing so is more vital than ever in today’s working environment.

By Alexandra Walsh

The impact of the COVID-19 pandemic and the ensuing Great Resignation amongst the U.S. labor force has resulted in unplanned challenges for utilities responsible for protecting critical infrastructure.

Not only are utilities operating with strained resources as the pandemic has impacted their workforces and customers, but at the same time, the threats to energy infrastructure have only increased with construction and homeowner excavations on the rise.

Utilities across the nation are reporting similar to increased volumes of one-call center/811 tickets due to a rise in construction and maintenance activity.

The number of events reported by the Common Ground Alliance’s (CGA) Damage Information Reporting Tool (DIRT) for the United States and Canada totaled 475,770, almost half a million, in 2020.

Understanding Root Causes

The Occupational Safety and Health Administration has specific excavation requirements (29 CFR 1926.651) designed to protect employees and prevent accidental damage to underground installations, including establishing the location of such underground installations prior to beginning excavation activities.

In the groundwater industry, the possibility of damaging underground utilities exists at every drilling site. Inadvertently severing an underground power line, rupturing a natural gas line, or damaging other underground utilities can result in costly consequences in terms of disrupting essential services, the costly repairs, downtime, and potentially serious injuries or death.

Year after year, hundreds of thousands of damages occur, and most of them can be attributed to the same handful of persistent root causes, according to the CGA. To prevent these incidents, it is important to understand the possible causes and the industry practices that are in place.

Of the 26 root-cause options, the top five reasons for underground utility damage in 2020 accounted for nearly 70% of damage events with a known root cause and looked notably consistent with past analyses. Key findings include:

  • Failure to notify the one-call center/811 remains the largest individual root cause.
  • Excavation done prior to verifying marks by a test hole combined with failure to maintain clearance make up the most consistent causes of damage due to excavator error in the field.
  • Abandoned facilities and locator error together make up the greatest causes of damages due to locating issues.

Calling 811 First

According to the 2020 DIRT Report, calling 811 before drilling or digging is the most important precaution that professionals can take before intrusive activities. When an excavator, a driller, or other party performing intrusive activities notifies a one-call center before digging, damage can be avoided more than 99% of the time!

This step was simplified in 2007, when the Federal Communications Commission (FCC) designated the toll-free 811 number to be the national “Call Before You Dig” number for the United States.

Anyone who plans to dig should call 811 or go to their state 811 center’s website a few business days before digging to request that the approximate location of buried utilities be marked with paint or flags so that you don’t unintentionally run into an underground utility line.

In the groundwater industry, the possibility of damaging underground utilities exists at every drilling site.

When you dial 811, you will automatically be connected to a representative from your state’s 811 center who will ask you simple questions about the location and details of your digging project. If you make your request online, you will enter the same information into a form.

Either way, you will receive a ticket number and instructions for how much time utilities have to respond to your request, as well as how to confirm that all utilities have responded before you can safely begin your job.

Hearing Back from Utilities

State laws vary, but generally, utility companies have a few days to respond to your request. Utilities will send out locators who will come to your jobsite and mark the approximate location of buried utilities with paint or flags so that you can avoid them.

Each utility type corresponds to a specific color of paint or a flag. For example, gas lines are marked with yellow paint or flags. In addition to waiting for markings, you must use the information on your ticket to confirm that all utilities have responded before you can begin your work. On average, between seven to eight utility operators are notified for each request.

Confirm that all affected utility operators have responded to your request and have located accurately. State laws vary on the process for confirmation, so please check with your local 811 center for more information.

If you see clear evidence of a utility, such as an above-ground marker, manhole cover, or utility box, but no utility marks, please contact your 811 center right away so that the utility can be notified.

Respect the utility marks (paint or flags). The markings provided by utility operators are your guide for the duration of your project.

If you are unable to maintain the marks during your project, or the project will continue past your request’s expiration date (varies by state), contact your 811 center to ask for a re-mark.

Drilling Near Underground Utilities

Finally, drill or dig carefully. State laws generally prohibit the use of mechanized equipment within 18 to 24 inches on all sides of a marked utility, which is called the tolerance zone.

If you must drill or dig near the marks, hand dig or use vacuum excavation to expose the facility. After exposing the facility, avoid using mechanized equipment within the same tolerance zone.

Utility locates and markings are often made in utility easements only, not on private property. Therefore if you are drilling or doing other intrusive activities outside easements, the underground lines will not be marked.

There are also many variables concerning locating and marking underground utility lines. These include:

  • Some utility owners take the position that a service line belongs to the property owner.
  • Power/communication cables and water/sewer lines serving buildings of educational institutions, government complexes, and office parks are on private property and are not covered by one-call.
  • One-call locates do not provide depth, but rather a window of horizontal space where utilities are estimated to be buried.


Excavators, including drilling operators, should establish a detailed work plan and train their employees on the proper procedures for:

  1. Determining the locations of underground utilities
  2. Contacting and coordinating with the local one-call agency and utility companies to establish the locations of the underground installations
  3. Taking the necessary precautions to prevent damaging underground utility installations.

If or when an underground utility is damaged, notify the utility operator immediately. The utility operator is in the best position to determine the hazards associated with the damage and implement appropriate countermeasures. If the damage results in the release of hazardous gases or liquids, both the utility operator and appropriate emergency response officials should be notified immediately.

Alexandra Walsh is the vice president of Association Vision, a Washington, D.C.–area communications company. She has extensive experience in management positions with a range of organizations.