Enter 811, a free nationwide service that allows homeowners to request a "locate" of their various electrical and water lines. While the 811 service is easy to use (all you have to do is call 811 or make a request online), the service does not guarantee that all your lines will be located for free.

So we did some research of our own to find out what the 811 service does and does not cover, and how you can prepare to locate all your lines before you start your next digging project.

What is an 811?

Before we discuss how to use 811, it's helpful to know a little more about the structure of this nationwide service.

"The 811 service works by providing a central point of contact for anyone planning an excavation to notify underground utility operators of their intentions," says Logan Cox of John the Plumber.

Whenever you call 811 or make a location request online, the operator notifies all the relevant utility companies in its network - including electricity, gas, water lines and so on.

The individual companies will then come to your home and mark their respective lines with coloured flags or spray paint, according to colour standards set by the American Public Works Association. This means that whatever country you live in will be marked in red for power lines and cables and in yellow for natural gas and oil.

What the 811 doesn't cover

The tricky part of all this is that while many utilities are in the 811 network, some are not.

"Companies choose whether or not to participate in protecting their underground facilities," says Benjamin Dierker, executive director of the Alliance for Innovation and Infrastructure.

In some cases, state laws require companies to use the 811. however, you won't know what your state requires until you create a locate request.

Another pain point to remember is that utility companies only locate their lines. Therefore, don't expect your electric company to mark gas lines, and vice versa.

You may also have private lines (i.e. owned by you or your landlord) that are not the responsibility of the utility company. This can be a tricky distinction to make. But with some research, you can sometimes determine where your private lines are.

"If the area you're digging is in front of the meter or in your front or side yard, it's usually a utility that 811 will have the locator mark," says Dierker." If it's behind the meter, it's probably a private line."

How do you mark your private utility line?

The company only marks a certain point between the road and your home, so it's safe to assume you have some unmarked private lines in that area as well.

But you know what they say about assumptions - don't do it. Instead, once all your local utility companies are out, consider hiring a private locating company to do the job.

"Digging without identifying all the lines," says Dierker, "is not recommended." A Google search for 'private utility locator' will bring up results." Then shop around for reputable companies and competitive prices.

Tips for using the 811

Here are some other tips for accurately marking all lines before you start digging:

Plan ahead

Before calling 811, have a detailed outline of your proposed project. This will ensure that the utility company does not mark areas unnecessarily and will focus on simply marking underground lines in the area you plan to excavate.

Surveying your property

Determine what types of utilities are used on your property. For example, if you know your home has a gas stove but no yellow lines are marked, it may be that nothing has been marked yet.

Check your 811 status online

You can always go online to check the status of your 811 request. There, you can see exactly which companies have been contacted and the status of your request - i.e., whether they've been to your property to mark their lines.

After 811

Always start by using 811 and see which of your local providers it works with. Once those companies have marked their lines, then contact the rest of the vendors who are not on 811. Finally, hire a private locating company to do the job.