Popular in Canada for 50 years, hydroexcavation only started gaining traction in the U.S. about 15 years ago. It still hasn’t caught on as much as it should, according to Tom Jody of Vac-Con in Green Cove Springs, Fla., and there is still huge potential for growth.
While many people may view hydroexcavation as a method for safely exposing underground utilities, there are several other uses, as well. “There are some situations where it’s a necessity because it’s impossible to get an excavating machine into a location,” says Jody, Vac-Con’s marketing director. “Take for example getting behind a home in a residential neighborhood to expose the foundation to repair a utility line or drain tile.”
There are also times when hydroexcavation is the easiest method. Besides daylighting (potholing), it is useful for things like installing power poles, excavating for water valve replacements, trenching, and even general excavation. “It is very precise; think about excavating a trench between someone’s prized flower garden and the wall of their house,” he says. “That’s something you can do with hydroexcavation that you couldn’t do with even the smallest of excavators. The applications are myriad and the equipment is relatively simple.”
The key pieces of equipment are a vacuum hose and a line for pressurized water. Compressed air can also be used, in which case it is called vacuum excavation (the generic term for the process). The water or air loosens the soil, and the vacuum removes the soil. “It creates a very accurate excavation and less impact on the surrounding environment with a much neater work space because you’re removing the soil into the debris tank,” he says.
Using air or water greatly reduces the possibility of damage that is common with a metal bucket. “It’s very easy to sever a fiber-optic cable with an auger or backhoe,” Jody says. “You could be shutting down the transfer of information to and from an entire city that could result in tens of millions of dollars in revenue loss. No contractor wants that on their resume.”
Such accidents can happen even when underground utilities have been marked or mapped. “We’ve been on jobs where we had diagrams showing the precise locations of utility lines and after we expose them, they’re three feet off from where they were supposed to be,” he says. “There’s a huge amount of wiring and utilities underground in this country, to the point where you see dizzying pictures of all kinds of cables, wires, and pipes crisscrossing each other in one excavation.”
So why do we continue to have gas line explosions and other excavation accidents? Jody isn’t sure, but has several examples of contractors who weren’t even aware of hydroexcavation that could have prevented those incidents. “Part of it is just not knowing that the technology exists, but there are organizations around the country building awareness, including the Common Ground Alliance and local one-call groups that can help contractors become more familiar with it.”
Most communities in Canada have ordinances requiring vacuum excavation in certain situations, and Jody says that demonstrates how much growth potential there is in the U.S. “Most communities in Canada require utility location with vacuum excavation or some sort of potholing before you’re allowed to excavate,” he says. “In some cases, you’re not even allowed to excavate with a conventional bucket machine, you have to use vacuum technology to do it.” Vacuum excavation is even growing in popularity with fire departments and rescue operations, especially for trench rescues.
“I’ve done it in my garden with a Shop-Vac and garden hose,” Jody adds. That is a simple example, but he stresses that there is a learning curve to use the technology correctly. “In some cases, the less water you use the better you are because you’re not creating slurry. Instead, you are creating moist soil you can use for backfill. You may not be able to do that with some soils and materials.” Equipment manufacturers and rental agencies offer the training for basic operation. And there is specialized equipment available for specific applications.
Some contractors are now exclusively doing vacuum excavation and rental equipment is readily available. Jody expects growing pressure in the U.S. for hydroexcavation. “If you have a backhoe,” he adds, “chances are you are going to be involved in a job somewhere that’s going to need it.”