Just How Deep Are Your Utilities?
Subsurface utilities are concealed by layers of dirt and stone, and so there’s often a question of how deep they are. Obviously there’s a need to connect to these services, so they can’t be that deep, but they also should be deep enough to avoid damage from typical surface work. So, how deep can your utility lines go? Why is depth so important when it comes to working around utilities and how does our team at Trinity uncover the exact depth?
To answer the first question, it can vary depending on location and utility type. Surface features would indicate an area where the utility connects to the surface. Digging around these without understanding what’s underneath would generally be a bad idea as there’s an absolute guarantee of utility structures buried under them. Usually there is a minimum of 18 inches underneath the surface that utilities are buried, but we’ll go into this more. Electric and communications lines fall around the range between a foot and a half to 2 feet of ground cover for easier access and maintenance. Gas lines typically fall around 3 feet in depth. Water and sewer lines are typically 3 to 4 feet deep depending on the climate, but they can be deeper. Some sewers are buried between 20 and 30 feet below the surface. You may think that the max depth utilities will be found is around 30 feet, but there are cases where they will go deeper. Some heavy duty fiber optic cables, traveling under rivers and bodies of water, will be buried over 100 feet deep to prevent damages!
“So, I can dig 18 inches before I hit something?” Not necessarily. Some utilities are buried less than the typical minimum ground cover. Gas lines, which can be incredibly dangerous if struck, have been found to be buried within 12 inches of cover. Cable lines may not even be buried at all — sometimes they are positioned on the surface and grass is allowed to grow over them, making them incredibly easy to strike by accident. While ground penetrating radar can help you determine the horizontal positions of utilities and our team relies on it to determine what to avoid, there’s never an 100% guarantee of depth. While there are typical standards for making sure utilities fall within certain depths, there’s no guarantee of an exact depth every time without Level A ASCE subsurface utility engineering data, which is only gained by uncovering the utility.
In order to get this information, our team at Trinity uses vacuum excavation investigations to dig test holes and trenches using a safe air or hydro digging process. This prevents damage to utilities that would occur with the use of shovels or heavier machinery. Once we uncover the utility line, we physically measure the distance from the surface down to the top point of the utility. In doing this, we not only get the depth of the utility, but also determine the shape of the utility, direction, and other conditions that help our clients make decisions. It also helps us determine how utilities may overlap. Gas, water, electric and communication lines will typically fall within the same depth range, so understanding how lines may overlap and intersect is important in maintaining operations. If you need to understand the depth of your utilities, call our team at Trinity Subsurface to safely dig around your lines through vacuum excavation techniques. Visit our full website to find out more information regarding our utility services.
