Hydro Excavation & Hydrovac

A hydrovac rig combines two pieces of equipment on a single chassis: a high-pressure water system and a high-flow vacuum recovery system. Water is heated and pressurized through a wand to roughly 2,000-3,000 PSI, high enough to break and slurry typical soils, low enough that a glancing hit on a buried pipe or cable does not damage it. As the wand cuts, an 8-inch vacuum hose alongside the operator pulls the resulting slurry into the truck's debris tank in real time. The hole develops as fast as the operator can sweep, and the spoil never piles up around the dig.

The safety case rests on one fact: no mechanical contact. Backhoes and trenchers cut through whatever they meet. Hydro excavation cuts soil and is functionally inert against the targets that matter, fiber-optic conduit, gas mains, fiber bundles, copper telecom, water mains, electrical primaries. That changes the math on damage prevention. A backhoe operator who clips a 4-inch gas main creates an incident; a hydrovac wand that brushes the same main exposes it for inspection.

It's also fast for what it is. Compared with hand-digging, which has historically been the only "safe" method around live utilities, hydrovac runs 3-10× the production rate. Compared with mechanical excavation, it's slower but eliminates the strike risk and the rework that follows a hit. For the right job (small dimension, buried utilities present, no tolerance for damage), it's simply the right tool.

Hydrovac is the right method when: existing utilities are in or adjacent to the dig footprint, the dig dimension is small enough that production rate doesn't dominate cost, the spoil has to be removed cleanly (no piles on adjacent surfaces), the substrate is frozen or otherwise tough on mechanical equipment, or a strike would cause damage out of proportion to the job's cost. Common scenarios: locating and daylighting before adjacent backhoe work, potholing for engineering survey, exposing existing utilities for tie-in, slot trenching in a roadway, vault and manhole cleanout, and any dig where the locate paint is dense.

Mechanical excavation is the right method when: the dig is large-volume, no utilities are present (or have been positively cleared by daylighting), production rate is the dominant cost, and the substrate is suited to a bucket. The two methods are complementary, not competing, most projects of any scale use hydro to expose what's there and a backhoe to move what's not.

Cowart's role on most projects is the hydro phase. We work with the general contractor or the utility's contractor and own the daylighting, potholing, and emergency-exposure scope while a separate crew handles the bulk dig.

The slurry that goes into the debris tank has to come back out somewhere. For most hydrovac contractors, that somewhere is a third-party disposal site, which means a transport vendor, a tipping fee, and a separate paper trail per load. The cost shows up on the customer's invoice as a pass-through and tends to be vague.

Cowart hauls hydrovac spoil to its own treatment plant in Carrollton, Georgia under its own DOT number. For non-hazardous spoil (the vast majority of hydrovac jobs), the disposal step is integrated, characterized, and priced predictably. Your project doesn't get held up while the truck waits for a slot at a third-party transfer station; it doesn't get a surprise charge for a tipping fee adjustment; and the disposition documentation comes out of the same system that generated the vacuum job.