The first step for safer digging happens long before the shovel hits the ground. Damage prevention relies on communication and collaboration between parties through One-Call centers. The notice of proposed excavation is the first step in this process, but it is more than just making a call.

Error and miscommunication can routinely occur on job sites, even when proper notice of proposed excavation is made. That may be because of an error on the excavator’s end describing the site or the One-Call Center’s end inputing information and notifying utilities; it could be the utility operator had incorrect maps or even that the locator made a mistake. In fact, according to the Common Ground Alliance (CGA), approximately 70 percent of known root causes happen after notification was made. While no silver bullets will solve the entire damage prevention problem, several known and proven technologies exist to level hurdles still standing in the process to streamline and improve safety.

Safer digging starts before the shovel hits the ground. In every state, homeowners and excavators are required to call 811 before breaking ground to let the One-Call center know about their plans. This triggers notice to utility owners/operators and locators to arrive on site and mark the area to reveal the type and location of any underground infrastructure. These markings are why damage is avoided in most cases; they denote the presence and location of things under the surface with great accuracy. But another kind of marking is also critically important and it can happen before the beginning of the dig. In fact, it can happen even before calling 811.

White-lining is how excavators show the specific area they intend to dig. To perform white-lining, a homeowner or excavator can utilize spray paint, flags, stakes, or even strings to mark off the proposed dig site. This can be vital information for the utility operator or locator to have because it narrows the scope of the project. Picture a homeowner who calls 811 and says he is digging in his front yard to plant a tree. If he lives on a one-acre lot, there may be nearly half an acre of land for the locator to mark and identify subsurface utilities. This large area increases the chance for oversight, mismarking, miscommunication, fatigue, and other issues with significant consequences.

Now picture the same scenario, but with a five-foot diameter white circle spray painted or marked off in the center of the front yard. There can be no doubt about where the homeowner intends to break ground, and this gives utility operators and locators better information to work with. They can efficiently mark utilities in the vicinity of these pre-markings and avoid wasting time and resources marking areas not within the scope of the project.

Physical white-lining is a basic step, which requires no added technology beyond a can of spray paint, a handful of flags or stakes, and some time. It is not without cost, however, and excavators may have to visit multiple sites, mark off large areas or complex shapes for the proposed excavation, or even make extra trips to the same dig site. The benefits outweigh the costs, because a damage event leads to a ripple effect of costs including damage repair, emergency response, lost productivity, delayed work, and costly litigation to determine and settle ultimate liability.

Fortunately, there is a more advanced option to physical white-lining that packs the same if not greater benefit and saves trips to the site. That is electronic white-lining (EWL) (or virtual white-lining). Like the name implies, this technique utilizes electronic platforms to identify a proposed dig site virtually.

You can picture an overhead perspective or GoogleMap view of the homeowner’s yard mentioned above. Rather than walk off his acre of property to spray paint a large circle, he can pull up his computer or tablet and simply draw the circle on the map where the excavation will occur. This process can be done on the One-Call center’s web-entry system and it allows the One-Call center personnel to know exactly which utilities to notify while also allowing utilities and locators to screen tickets more accurately (to determine if their facilities are in or near the intended dig site) and to check the area of the locate from their office.

For the professional excavator moving from job site to job site, electronic white-lining may spare multiple trips to and from job sites, reduce the need to conduct physical marking, and help the locator complete his work faster and more accurately so the excavation work can continue efficiently.

When CGA and its 16 diverse stakeholder groups looked at the issue, they unanimously designated white-lining as a best practice in 2017. Not only this, but they point to electronic white-lining as desirable where it is offered. At least 23 states require white-lining in the notice of proposed excavation process.

Unfortunately, CGA and many states propose that it is a best practice to pre-mark or white-line only when the proposed excavation site cannot be accurately described or detailed by calling 811 or through a web-entry locate request. Many errors and much miscommunication can be avoided if white-lining is required as the standard default first step – there is always a chance one party thought the site was accurately described, but more information and data can only add value and reduce incidents, not to mention spare costs.

In spite of its relatively weak best practices statement on the matter, CGA has gone as far as to say that the ideal excavation project by the year 2030 would begin with electronic white-lining. This idealized dig of the future beginning not only with white-lining, but electronic white-lining signals that CGA knows how critically important this technique and technology is to the damage prevention process. Through Technology Reports, white papers, and special working groups, CGA and industry participants have more publicly declared how important pre-marking is and the benefits of doing so virtually.

What is most important is that this technology exists, is proven, and is ready to implement nationwide. Every One-Call center in the United States has a web-entry portal where homeowners or excavators can submit notice of their proposed excavation and request a locate. Many of these also integrate GoogleMaps or similar platforms for excavators to provide unambiguous delineation of the dig site.

Electronic white-lining should not only be a best practice and norm, but an essential first step to safer digging long before the shovel hits the ground. CGA, states, and other stakeholders should not view this as a secondary option or alternative when the site cannot be explained well, but a first step and companion to any and all proposed excavation notices.

This overview of white-lining and its electronic evolution merely introduces the issue. Stay tuned for the next four blogs in this series explaining the environmental, economic, efficiency, and investigative benefits for electronic white-lining. Now that Safe Digging Month is over, it is as important as ever to remain vigilant and focused on ways to improve damage prevention. By the end of this blog series, we hope stakeholders and the public will see the need, benefits, and urgency to bolster the entire damage prevention process with innovative technology.


Read the full series:


Safer Digging Part 1: Before the Shovel

Safer Digging Part 2: Click Don’t Call

Safer Digging Part 3: Keep it in Park

Safer Digging Part 4: Saving Time Saving Money

Safer Digging Part 5: Investigating a Damage


Written by Benjamin Dierker, Director of Public Policy


The Alliance for Innovation and Infrastructure (Aii) is an independent, national research and educational organization. An innovative think tank, Aii explores the intersection of economics, law, and public policy in the areas of climate, damage prevention, energy, infrastructure, innovation, technology, and transportation.