The Association of Equipment Manufacturers (AEM) has released a Top 10 list of common underground utility myths, along with the facts for safe underground utility installation, repair and maintenance.

Safe machinery operation saves lives, and equipment manufacturers want underground utility industry professionals to always think safety on the jobsite.

AEM compiled the list to kick off the first phase of its new Underground Utility Awareness campaign. Equipment covered includes horizontal directional drills, vacuum excavators, trenchers, and related underground equipment. Through the campaign, manufacturers are collaborating with underground utility organizations and other industry stakeholders to get the message out that underground utility installation is safe, economical and efficient.

“We wanted to dispel these myths by emphasizing guidelines and job planning that should be followed for the safety of workers and the community,” stated William Bernhard, AEM technical and safety services manager.

For more information on the Underground Utility Awareness campaign and to get involved, contact Bernhard (, tel: 414-298-4106).

The list

AEM and equipment manufacturers encourage industry professionals, whether they’re new to the job or veteran workers, to take the time to review these common myths and follow industry best practices to help save lives and prevent property damage.

1. “Depths of utilities can be assumed.”

Locator depths are approximate. Depths of utilities absolutely cannot be assumed. Even within distances less than a city block, a utility may dip or rise in depth. The surface grade often changes, sometimes dramatically, since utilities were originally installed. Utilities are often installed before excavation, fill and development happen that can change the surface grade dramatically. Utilities must be exposed to verify location and depth.

2. “It will never happen to me.”

That’s what every contractor or operator thinks, but utility strikes happen every day. Cutting corners and rushing to get the job done, thinking “I’ve done it a million times and nothing has happened,” getting lazy or complacent on the job… all of these can lead to major consequences. You have an important job to get utilities in the ground, safely and effectively. The risk is too great to depend on chance.

3. “Exposing to the depth of the utility is good enough.”

Exposing just to the depth of the existing utility is not proper practice and may violate OSHA regulations. You need to verify that no utilities are hiding underneath and always expose to the depth of the intended bore path. Visually observe the drill head as it passes the utility, and again during each pass of the reamer. The reamer can shift in the bore during pullback and strike a utility that appeared to have plenty of clearance.

4, "Just drill deeper to avoid existing utilities.”

Drilling deep creates problems such as locating and exposing for current and future excavation. At approximately 10’, locators become less accurate with locating the underground infrastructure. If the existing utility goes undetected, an underground strike can occur. Also, best practices dictate that the existing utility being crossed be exposed to the depth of the intended bore. That is difficult for deeper bores and if the line at that depth is ever damaged, the utility will have to dig deeper requiring a longer response time and greater expense.

5. “Sewer lines don’t need to be or cannot be located.”

If a sewer line is breached during a utility install, the sewer will eventually clog due to the intersection of the newly installed utility. To relieve the clog, a plumber will run a snake into the sewer and damage the line. If it is an electric line, the plumber can be electrocuted. If it is a gas line, the gas will migrate into the sewer and ignite once inside homes or businesses.

Several methods exist for locating sewage lines. Technologies like ground penetrating radar make it easier to locate lines and inspection camera systems are used to verify the lines were not breached.

6. “No locate marks = no utilities.”

If there are no marks, this could mean that it was not yet located. Many states have a positive response system so that it can be verified that all utilities have cleared the area. 

On-site, privately installed lines may not be recorded by the utility companies or located by the locating service. Inspect the area for evidence of underground activity, disturbed and repaired soil or pavement, utility boxes, conduit coming out of the ground, etc.

7. “My responsibility for damage prevention ends when I call 811. If something happens, 811 is liable.”

811 does not locate utilities. They coordinate with the utilities and their contracted locating services to have the area located. It is the responsibility of the excavator to verify that locates have been completed and are correct. This includes contacting utilities that don’t subscribe to 811, looking in the area for signs of utilities (outbuildings, pipeline markers, light poles, utility boxes, meters, etc.) and exposing the utilities to verify the locates. If an excavator damages a line, there are always costs to bear and effects on reputation.

8. “Exposing utilities (potholing) is included as part of the contract price for the drilling.”

This shouldn’t be assumed. To ensure potholing activity is included and is not shorted, it is recommended to separate this activity from the drilling in the quote. The project owner and contractor should work together to emphasize this as an important and integral part of the job.

9. "We have to accept whatever the caller gives us.”

When a contractor calls the Call Center or Utility, both parties have to be explicit and detailed with the information provided so an accurate and safe locates can be made.

10. “Electric strike alert systems can predict an electric strike.”

In some cases, the system may activate in the proximity of an energized line, but it cannot be relied upon to detect the line before a strike happens.  If the electric strike system activates, always assume an electric strike has occurred.  

Some strike systems detect a strike using only voltage detection via a voltage limiter. The voltage limiter is located away from the machine on a ground stake and detects the voltage difference between the ground stake and the drilling machine.

Other strike systems use both voltage and current detection. In addition to a voltage limiter, a current coil detects current flowing through the drill string.  The system will only activate the alarm when voltage, current, or a combination of both voltage and current is above threshold limits.  

For either system, if the alarm sounds, assume a strike has occurred. 

ICUEE-The Demo Expo

The Underground Utility Awareness campaign is aligned with AEM’s ICUEE-The Demo Expo trade show, to be held September 29-October 1 in Louisville, KY.  ICUEE focuses on the newest technologies, innovations, insights and trends affecting the utilities and utility contractors (electric, telecom/cable, natural gas, water, wastewater sectors).

ICUEE education will feature a five-star lineup of more than 60 education sessions from leading industry groups. Visit for more information. 

About the AEM

AEM is the North American-based international trade group providing innovative business development resources to advance the off-road equipment manufacturing industry in the global marketplace. AEM membership comprises more than 900 companies and more than 200 product lines in the agriculture, construction, forestry, mining and utility sectors worldwide.

AEM assists manufacturers and the off-road equipment industry in fostering safety best practices through the association’s extensive array of safety manuals, videos and related training materials. Visit for more information.