# How to Calculate the Cost of Vacuum Excavation

March 6, 2024

Editors' note: This article has been updated since it was originally published in 2019. Content was provided by Vermeer.

Vacuum excavation, also known as potholing, is a method of exposing utilities using water and suction. Vermeer offers some tips on how to estimate the operating costs of running vacuum excavators.

Vacuum excavators uncover utilities using high-pressure water, but the material can’t merely be piled up near the hole and filled back in. The soil mixed with water is considered spoil, or slurry, and must be transported to disposal sites, which requires effort and costs not associated with uncovering utilities with an excavator or backhoe loader.

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“To estimate potholing expenses, contractors need to have a general understanding of what utilities their crews will encounter near the proposed drill path,” says T.J. Steele, product manager at Vermeer. “The number of holes and depths need to be considered, as well as the site’s proximity to water and a disposal site. Depending on the customer, getting that information isn’t always easy, which makes estimating a bit of a moving target.”

## How much does vacuum excavation cost?

To get a rough estimate of operating costs for vacuum excavation, Steele recommends starting with a hole count.

“Each hole will usually be about 1 foot in diameter, but depths can vary,” he says. “Depending on ground conditions and climate, crews should be able to determine the approximate depth of each utility. So, if they need to excavate to a depth of 5 feet on average, they remove around 4 cubic feet of material for each hole. However, the volume of liquid being suctioned into the spoil tank also needs to be accounted for. Fluid volume can vary depending on the soil conditions, but crews can usually expect it to be a 1:1 ratio.”

“I’ve heard from contractors working in large cities that their crews often have to drive to a location outside of city limits, and they pay substantially more than they used to just a few years ago. It’s a real issue,” he says.

Transport weight of the truck and trailer vacs must also be considered. Steele recommends calculating the distance to a disposal site, researching dump costs, and studying DOT weight regulations during the bid process.

“After a project is completed, contractors should compare the estimated operational cost with actual expenses,” he says. “Going through this process will help them dial things in for future projects. Also, in some instances, investing in a way to take some of the variability out of a project is a better approach.”