A hydro excavator is a machine that uses water pressure and a vacuum tank to remove soil from on top of utilities without damaging the fragile utility components, such as wiring, and water and sewer lines. The hydro excavator is typically mounted on a heavy truck chassis and utilizes an on-board vacuum pump and hose to draw the loosened soil out of the ground and into the truck's storage tank. Water for the hydro excavator removal process is acquired from local water hydrants or other sources, as needed. The water nozzle is affixed to a large-diameter flexible vacuum hose with a non-metallic tip to protect the underground utilities from damage from incidental contact with the hose.
In cases of underground utilities requiring uncovering, a hydro excavator is often the preferred method of removing the covering soil. A typical excavator equipped with a steel bucket/shovel could easily destroy a fragile sewer tile or wiring. By using the hydro excavator, a jet of water is used to loosen the soil while a vacuum hose sucks the water and soil up into a waiting storage tank. The hose is equipped with a non-metallic tip to prevent any damage to delicate wiring from contact with the hose.
A special vacuum pump is required to remove an exact amount of soil with the amount of water used. Without the correct vacuum pump, the soil removed could be of the wrong consistency to be properly reused. This could result in excessive time spent on the job, an overage of water used and excessive dumping of the materials, which could lead to much greater costs to complete the project. Using the proper hydro excavator will ensure the most economically- and environmentally-friendly results. Often, the removed soil, if free from contaminants, can be discharged back into the removal site, saving on fill costs and dumping expenses.
The hydro excavator units have been used successfully for uncovering tasks from underground utilities to rescue and salvage missions at mudslide sites. The powerful removal action of the water coupled with the vacuum suction of the hydro excavator creates a virtually water-free area directly below the hose nozzle. This allows operators to see clearly what is being uncovered and prevents accidental damage from occurring due to blind excavation practices. The use of a hydro excavator also ensures that no more material than is absolutely required is removed from the excavation site, thereby preventing any weakening of the substrate due to undermining.