Utility Strike Prevention: A Working Playbook
Strikes are overwhelmingly preventable, and the causes are boringly consistent. Here is the sequence that removes them.
The Six-Step Sequence
- White line the dig area so responding locators mark the right ground.
- File the one-call ticket with the notice period your state or province requires.
- Wait for positive response from every notified member. Silence is not clearance.
- Locate the private side — everything past the meter is outside the ticket and needs its own sweep.
- Pothole what the plan depends on — crossings, foundations, bore paths. An estimated depth is not a depth.
- Respect the tolerance zone — hand or vacuum digging only, inside the buffer your jurisdiction defines.
The Four Recurring Causes
Damage-prevention data from every jurisdiction tells the same story. Strikes cluster around: no ticket filed at all; digging before every member responded; marks that were ignored, destroyed, or never verified as present; and mechanical excavation inside the tolerance zone where soft digging was required.
A fifth cause sits outside the public system entirely — the private line nobody marked because nobody was obliged to. That one does not show up in one-call statistics, and it is why a private sweep is standard on any high-consequence work on private property.
Verify the Marks Before You Trust Them
Walk the marks before the machine starts. Are all the expected utilities represented, or did a member respond "no facilities" for something you can see a meter for? Are the marks still legible? Do they run where the site plan says they should, and if not, which one is wrong? A mark that contradicts the drawing is information, not an annoyance — one of them is wrong and you need to know which before you dig.
The Tolerance Zone Is Law, Not Guidance
Every jurisdiction defines a buffer on either side of a mark within which mechanical excavation is prohibited and only careful hand or vacuum digging is permitted. The width differs by state and province, so check the one that governs your dig. The zone exists because a mark is an approximation carrying real uncertainty — coupling, bleedover, and soil conditions all move a trace — and the law builds a margin around that uncertainty rather than pretending it does not exist.
Report Everything, Including the Small Stuff
A nicked cable jacket or a scraped pipe coating is a reportable damage even when nothing leaked and nothing went dark. Coating damage that goes unreported becomes a corrosion failure later, and liability follows the crew that left it compromised. Report to the facility owner immediately, document it, and let them decide whether it needs repair.
If you smell gas at any point, leave the area first and call the gas utility's emergency number or 911 before anything else.
After a Strike
Once the immediate hazard is handled, do not resume digging on the same ground on the old information. A strike is evidence that the picture was wrong somewhere. A post-incident sweep of the work area — with both instruments, on the private side as well as the public — is how you find out whether the thing you hit was the only thing that was missed.
Frequently asked questions
What is the single most common cause of strikes?
Not notifying at all, followed by digging before every notified member has responded. Both are process failures rather than technical ones, which is why damage-prevention programs focus so heavily on the ticket and the response rather than on equipment.
Who is liable when a line is hit?
Generally the excavator, with the specifics set by state or provincial law and by the facility owner agreements. Liability turns on whether the ticket was filed, whether responses were received, whether marks were observed, and whether the tolerance zone was respected. Skipping any of those steps tends to move the whole exposure onto the excavator.
If the marks are wrong, is that a defense?
Not on its own, and it is a bad plan to rely on. The tolerance zone exists precisely because marks carry uncertainty, and jurisdictions expect excavators to work accordingly. Where the depth or position genuinely matters, the answer is verification — a vacuum test hole that turns an interpretation into a measurement.
Do private locates reduce strike rates?
They address a category the public system structurally cannot: lines nobody is obliged to mark. Whether that changes your outcome depends on where you are digging. On public right-of-way work with all-member coverage, a ticket goes a long way. On private property, most of what is in the ground is outside the ticket, and a sweep is the only thing that finds it.
Related guides
View all811 Call Before You Dig: What It Covers and What It Misses
Call 811 — or your provincial one-call centre in Canada — before every dig. Then understand precisely what the ticket did and did not cover, because that gap is where most private-property strikes happen.
How to Read Utility Marks on the Ground
Marks are a language, and most of the people digging near them were never taught to read it. It takes ten minutes.
When to Hire a Private Utility Locator
One-call is free, required, and incomplete. Here is how to tell whether it covers your job or stops short of it.
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