With more than 20 million miles of buried infrastructure in the United States and more being added every day, it has never been more important to adhere to best practices in excavation to ensure the safety and connectedness of your employees and the communities where you do business.

Unfortunately, damage to buried utilities is still a far more common occurrence in the U.S. than anyone would like it to be: Every 9 minutes, an underground line is struck because someone decided to dig without first calling 811. The financial impact of these damages includes not only the downtime incurred when excavation work is paused and the downtime to businesses relying on utility service, but also repairs to the damaged infrastructure and possible fines. The impacts of damaging a buried utility line can also be human: Serious injury and death can result from striking a gas or electric line, or from generally unsafe excavation practices. No project, regardless of scope, benefits, or urgent necessity, is worth such dire consequences.

The good news is that stakeholders dedicated to preventing damages to buried utilities have worked to create a living, consensus-based Best Practices Guide to assist any organization that excavates. These stakeholders formed an association called the Common Ground Alliance in 2001, following a Department of Transportation study into damages to oil pipelines. Members representing a range of stakeholder groups and utility types have continued the study’s work in identifying root causes of damages to buried infrastructure and educating excavators and the public about how to dig safely around these lines. Today, the CGA has more than 1,700 members.

CGA’s Best Practices Guide serves its primary mission to identify and disseminate evidence-based practices for safe excavation. Now in its 15th edition, the guide is available online at Below are some common-sense steps distilled from the Best Practices Guide, which do not in any way replace the richer, more detailed practices in our full guide, nor do they substitute for a thorough understanding of your state, local, and municipal laws and codes governing excavation.


It is critical to be aware that excavation best practices begin before any dirt is ever disturbed. Planning a safe dig is an important step towards having a safe dig.

Planning should include all relevant stakeholders. Several Best Practices focus on the importance of planning a project properly, by working with existing facility owners and designers/architects, ensuring that existing facilities and new facilities are clearly included on design documents, and continually communicating with all relevant stakeholders. Taking these steps ensures that everyone is on the same page, and that you are benefitting from the knowledge and expertise of others as you site new infrastructure and work around old infrastructure. Some state laws now allow for “design tickets,” which provide general utility location information for early project planning purposes.

Educate your workforce on safety practices. Unfortunately, not all contractors educate their employees about skillfully, safely, and reliably digging. Be sure that your employees have all the necessary qualifications to complete their work safely.

Have buried facilities located. Simply calling 811 to have the approximate location of buried utilities marked on your dig site a few days beforehand is the single most important step you can take towards a safe excavation. When facilities are located prior to digging, there is a less than 1 percent chance of damaging a buried line. An additional best practice is to use white paint to outline your dig site prior to calling 811 to give utility locators the best possible guidance on where they should locate and mark facilities.

You can even schedule a pre-excavation meeting with facility locators. When working on a large-scale or unusual project—or whenever it is practical to do so—excavators can request a meeting at the dig site with facility locators to thoroughly review planned digging, high-priority facilities, and answer questions.

Document and preserve the markings. After the approximate location of buried utilities on your dig site have been marked with paint and/or flags, you should endeavor to take every precaution to preserve those markings and keep them clearly visible throughout the life of your 811 one-call ticket. You may also consider documenting the markings via video or photos, as it can be useful in the event that a line is later struck and an investigation ensues. You will want to have proof that your dig site was, in fact, located prior to digging. Please note that documenting and preserving markings is not a substitute for having your dig site re-marked once your 811 one-call ticket expires.


There are several steps contractors should take during the excavation process to keep the worksite safe.

Know what your “tolerance zone” is, and excavate in and around it carefully. The “tolerance zone” is the area around a buried facility in which reasonable precautions should be taken to prevent damage to the underground facility. Tolerance zones vary by state, but as a general practice, 18-24 inches on either side of a pipe or line should be considered the tolerance zone. Hand digging (potholing), soft digging, vacuum excavation methods, and pneumatic hand tools are a few recommended ways to excavate within tolerance zones, but these will vary based on climate and geographical conditions. Refer to your state, local, or municipal law for regulations regarding tolerance zones and excavation within them.

Use an excavation observer. An observer should assist the equipment operator when he or she is digging around known underground facilities, to warn the operator about proximity to the facilities.

Unmarked facilities should be reported. If you uncover an unmarked facility as you excavate, notify the facility owner immediately.

Damages should be reported as soon as possible. If you strike or damage a buried facility, you should immediately report it to the facility owner and the one call center. If the damage results in the escape of any flammable, toxic or corrosive gas or liquid or endangers life, health, or property, the excavator responsible should immediately notify 911 and the facility owner/operator, and take reasonable steps to protect everyone in immediate danger.

Refer to our full Best Practices for more detailed information about the steps you should take to guide safe and successful dig, and familiarize yourself with the relevant laws and codes. And, remember that 99 percent of excavations that were preceded by requests to locate underground facilities are without incident—so call 811 before you dig!


Khrysanne Kerr is vice president of communications with Common Ground Alliance. For more information, visit

Modern Contractor Solutions, July 2018
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