Congratulations on getting started on your residential or commercial project! But you might find yourself running into a snag if you don’t know if or where there are underground cables. There may be all sorts of lines buried, including fiber internet, cable television, and power lines. But how do you find them?
Before you begin any digging, you are required by law to contact Dig Alert. Digging without having these lines marked carries risks not only to your own service, but also to those in your vicinity. Cutting an underground cable could cause outages in your area. It is also highly dangerous, risking cutting a gas line or electric line. In California, you could be fined up to $10,000 if you do so negligently. The cost is much more (up to $100,000, depending on the consequences of an accident) if you know the law and proceed anyway.
Call 811 at least two working days before you plan to start digging and Dig Alert will alert utility companies that maintain underground lines in the area. Different types of lines are marked using this color-coded system. However, they will not mark private lines, so your work is not yet done! Dig alert is an absolute necessity, but it is not the only thing you need. You also need a clear picture of what else might be buried below the ground. In residential projects, you may find a previous owner of the home was a DIY enthusiast, which could bring surprises. It’s therefore very important to know the literal “lay of the land.”
Technically, the answer is yes, you can! But the more complicated answer is that it depends on the range of the metal detector you are using. The depth of utility lines will vary depending on the company, but most are generally installed between 24 inches and 48 inches deep. Most metal detectors from consumer stores are not designed to penetrate that deep. They typically will only sense objects about eight inches beneath the surface. To use a metal detector successfully, you would need a specialized unit capable of penetrating much deeper.
A much better approach than a metal detector is a method that will allow you to see a complete picture of what is beneath the surface. This way, you will get a clearer picture of where exactly the cables are, but you can also see other non-metal objects that may be buried in the soil. Our preferred method for utility location is GPR (Ground Penetrating Radar), a unit that delivers high-frequency radar pulses beneath the ground and uses the echoes from those pulses to image the ground beneath the surface. You can read more about GPR and what it is used for here.
While you can rent a GPR unit and do the work of scanning beneath the surface yourself, there are some drawbacks to doing so. It requires some training to interpret the results of a GPR unit correctly. If you misinterpret the results and cut into a line that was private, and thus not marked by the Dig Alert process, the results would still be costly and potentially dangerous. With the help of a skilled contractor, however, you can guarantee a clear idea of what lies in the soil and how to avoid it. Location professionals also have access to other tools that can be used in addition to GPR, such as line locators.