Watch Out for Underground Utilities

Follow these steps to stay safe when working around buried utility lines.

By Alexandra Walsh

In the suburbs or even in the middle of nowhere, there is a pretty good chance one or more utility lines or some other underground installation is buried beneath the surface.

Hitting a buried utility while excavating the soil can not only cause disruption of services to the general public, it can also result in natural gas being released into the atmosphere or someone getting seriously injured or killed from getting electrocuted caused from an underground electrical conduit.

In fact, if a water well drilling crew is instructed to work in an area where utility locations are not known, a worker can become exposed to an unexpected reaction resulting in either damage to equipment or unstable soil.

In recent years, the Occupational Safety and Health Administration has stated that one of the leading causes of excavation or trenching-related injuries is not providing a protective system. This includes planning ahead of time in locating nearby utilities.

First Steps

Before any excavating takes place, workers must first estimate where any buried underground utilities are located by contacting the appropriate service.

This means notifying the utility companies or owners involved to inform them of the proposed work within established or customary local response times. Ask them to establish the location of underground installations prior to the start of excavation work. If they cannot respond within 24 hours (unless the period required by state or local law is longer) or cannot establish the exact location of the utility installations, drillers may proceed but with caution, using detection equipment or other acceptable means to locate utility installations.

Concentrate on determining the exact location of underground installations when excavation operations approach the known approximate location of the installations.

“Call Before You Dig”

The most common reason workers hit underground installations is because they assume all lines in the area are buried at least 18 inches deep because, in most states, all lines are “supposed” to be buried at least 18 inches deep.

Any type of excavating or drilling at any depth always requires a call to 811 a few days before the project. Each state has specific guidelines for its “Call Before You Dig” program.

To prevent potential hazards, it is important to follow all pertinent excavation and trenching requirements. In addition to OSHA rules, workers should be aware there are many specific state, municipal, or local rules for Call Before You Dig.

OSHA Standard 1926.651(b)(1) states that the estimated location of utility installations—such as sewer, telephone, fuel, electric, water lines—or any other underground installations that reasonably may be expected to be encountered during excavation work shall be determined prior to starting an excavation.

To learn more about calling 811, including the program in your state, visit the Call 811 website at It has an interactive state map to make it easy to find information about local requirements.

Call 811 from anywhere in the country a few days ahead of working on excavations, trenching, or drilling and the call will automatically be routed to the local on-call center. The amount of lead time to allow for the lines to be marked varies as it is dictated by state law. But usually allow at least two to three working days, excluding holidays and the weekend, and then confirm that the utilities have been marked before starting to excavate.

OSHA Standard 1926.651(b)(2) says that utility companies or owners shall be contacted within established or customary local response times, advised of the proposed work, and asked to establish the location of the utility underground installations prior to the start of actual excavation.

Always wait the specific time required by the utility locating service, and once on the jobsite, always respect the markings and flags placed by the locating service.

Working Around Utility Lines

Here are additional best practices to avoid hitting underground utilities.

  • Never dig or drill until after all underground utilities have been marked. Paint, stakes, or flags of various colors will be placed to identify the approximate location of any buried utilities at the site.
  • Prior to starting work, have ready a completed site-specific safety plan outlining the steps for locating each utility, drilling methods, spotting, and communicating. Go over this plan with the work crew before each day’s activities.
  • Communicate to work crews the safety steps that are taken to protect each worker. This might be a company-specific practice involving lockout/tagout or using monitoring equipment on the jobsite.
  • Locate any underground utilities that are present inside the “tolerance zone” by using approved non-destructive digging measures. The tolerance zone is the area along each side of an existing utility line that has been marked. This area varies from state to state, but usually ranges from 18 to 24 inches from each side of the utility line. In some states, the tolerance zone is as much as 30 to 36 inches from each side of the utility.
  • Support exposed utility lines, if you need to, so they don’t collapse under their own weight. This may require placing a heavy timber or pipe across the top of the trench, and then tying a rope from the timber or pipe to the utility line to support its weight.
  • When digging with hand tools, ease up when you get near the underground utility. You want to avoid damaging the utility line while you are digging, so slow and easy does it!
  • Report immediately any damage accidentally caused to a buried utility, no matter how minor, to a supervisor. Damage to a buried utility that goes unrepaired or unreported could worsen over time and cause the line to crack, corrode, or rupture.
  • Use caution when backfilling near utility lines in excavations. Dumping a large heavy load of backfill soil directly onto an unsupported utility line could cause it to break. Firmly backfill the area beneath the utility line with soil before placing and compacting soil over the top.

PPE and Utilities

The importance of workers donning personal protective equipment (PPE) takes on an added dimension when working around threats from hidden utilities on the jobsite.

For example, many business owners and employees are unaware that fire hazards can result from combustible dust. These hazards are found in situations where workers can suffer life-threatening burns from natural gas explosions, flash fires, electrocution, and flying particles related to pressurized equipment.

The most useful strategy in selecting the correct PPE is to conduct a workplace job hazard analysis of each job to check that each hazard has been evaluated and can be prevented.


Drilling crews work around underground utilities every day. Doing so can be done safely as long as your company follows smart jobsite habits. The first step of course is finding out where the underground lines are located. Have them marked, respect those markings, and go home safe at the end of the workday.

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.