August 8, 2017

Excavating carefully: What to do after 811

You’re planning to dig, and you’ve done everything right. You called 811. You waited for utility lines to be marked. And you made sure every operator marked their utilities or gave you an “all clear.”

But as you begin you work, there’s just one more step—respecting the marks as you excavate carefully.

Because locating and marking pipelines isn’t an exact science, excavators should always assume the pipeline or utility could be anywhere between 18 and 36 inches on either side of the mark—a space known as the tolerance zone. (In many areas this space is defined by state or local laws, so always check before you begin work.)

To protect both you and the pipeline, use hand-digging tools like rounded shovels instead of mechanized equipment when digging in the tolerance zone. Never use sharp tools like pickaxes or pointed spades, and never stomp on a shovel with both feet. This is a sure way to damage a utility line.

While markings show the location of a pipeline, they don’t show its depth. Pipelines may have been installed at a prescribed depth, but years of digging projects and natural processes like erosion can lead to lines with shallow cover. Never assume the pipeline is buried deep in the ground.

Pipeline markings also come with an expiration date. Depending on the laws in your state, you may need to make another call to 811 if you are still working on the site two or more weeks after the lines are marked. You should also call 811 to have lines relocated if you’re still working and the marks are no longer visible.

Excavating carefully and respecting pipeline markings will keep you and others safe during your digging project, no matter how big or small. To learn more, please visit