Spec’ing a vacuum excavator

Selecting the right vacuum excavator for your business

With all of the different makes and models of vacuum excavators on the market today, choosing the right one isn’t necessarily an easy decision for anyone. However, answering a few easy questions can help narrow your search to select the right machine for your specific needs.

To begin, you need to consider the vacuum excavator qualities that a spec sheet can’t tell you. After shoring up your search, you can dive into the details.

Choose a manufacturer you can trust

Perhaps this is an obvious one, but when you’re in the market for any type of machinery, you need to start by narrowing the field to brands that have a solid reputation for dependability and service after the sale. Quality companies stand behind the machines they build and have dedicated in-the-field support to help minimize downtime.

For vacuum excavators specifically, you want a manufacturer that has been around for a while, understands the industry and has a robust dealer network so you have the assurance that they can support you and your crew no matter where you are working.

McLaughlin, a Vermeer company, has served the underground market for nearly 100 years and its products are supported by a worldwide network of dealers.


Most vacuum excavators are designed to perform the same functions. To narrow your selection process a bit further, you should look at the specific features that manufacturers have incorporated into their machines. Here’s a list of features to consider looking for:

  • What type of vacuum blower does it have? The blower creates the suction and most units on the market will use either a positive placement blower or a centrifugal blower. Positive placement blowers are great for potholing because they deliver a consistent volume of suction. Air volume will drop off with centrifugal blowers when pressure builds, which isn’t ideal for many applications.
  • You should also ask about the filtration system. Believe it or not, some vacuum excavators still use a baghouse filtration system — similar to what you would find on an old household vacuum cleaner. As you can imagine, that’s not the way you want to go.

Cyclone filtration systems are more effective than bag house systems, but not every manufacturer’s system can achieve the results. At McLaughlin, we equip Vermeer vacuum excavators with a standard three-stage cyclonic filtration system that reduces airborne particulates before reaching the final filter and vacuum blower. Our design helps prolong the filter life and reduces maintenance costs.

  • How easy is it to dump? When the tank is full, dumping the spoils shouldn’t be a labor-intensive job. However, some vacuum excavators’ lift door positioning doesn’t give the greatest ground clearance. You don’t have to worry about that with Vermeer vacuum excavators built by McLaughlin. Our patented, high-lift “cam-over” external hydraulic door gives you plenty of clearance, and we use a 360-degree seal to ensure you’re not losing any material as you’re transporting it to a dump site. Furthermore, all of the lift door components are on the outside of the tank — a reliable and simple design.
  • Does the tank have a washdown? Sucking up HDD fluids and spoils is a messy job but cleaning your vacuum excavator’s tank shouldn’t be. Choosing a machine that has an in-tank washdown will save you time and make it easy to remove any stuck-on debris.

Time to talk specs

By now, your search for the perfect vacuum excavator should be narrowed down. So, let’s dive into machine specifications.

  • Spoil tank size: Tank sizes can typically range from 300 to 3,000 gallons (1135-11,356L), and choosing the right tank size for your needs will depend on how you’re using your vacuum excavator.

If you’re primarily using a vacuum excavator to remove drilling fluids while installing larger diameter utilities or working in challenging ground conditions, like cobble, rock or sand, you may want to look at a tank on the larger end of the spectrum.

If you’re going to be using your vacuum excavator for potholing, you’ll likely want to choose a smaller tank size, so you have more maneuverability on the job.

CFM/Hose size: CFM, cubic-feet-per-minute, is the specification that manufacturers use to describe volume of air being moved. CFM ratings correlate with the diameter of a vacuum excavator’s hose. You should choose a hose size that delivers enough CFM of velocity to keep the material that is suctioned up suspended all the way to the tank. If material settles in the hose, you could end up with a clog on your hands. Keep in mind, it takes more horsepower to produce higher CFM of velocity, which will increase your purchase price and operating costs.

  • Gas vs. diesel: Many manufacturers, including McLaughlin, offer gas vacuum excavator models. Gas models tend to be a less expensive to purchase than similar sized diesel models. Gas vacuum excavators perform well in most ground conditions. However, diesel engines have the advantage when it comes to CFMs. So, if you’re working in cobble or tough clay, you may want to choose a diesel unit.
  • Trailer or truck: Choosing the right way to get your vacuum excavator to the jobsite is something you need to think about too. Trailers are nice because they can be unattached and left in one place, but they aren’t as easy to maneuver on the jobsite as a truck-mounted vacuum excavator. To make this decision, you need to determine your crew’s preference, and which is more productive for the type of work you’re doing.

There are a few things you should keep in mind no matter what you decide:

  • Weight: Whether you choose a trailer or truck mounted model, you need to make sure that you’ve got the right size truck to match it. With truck-mounted vacs, you also need to make sure that you’ll be able to abide by state weight restrictions with a full tank.
  • PTO drive or self-powered unit: When it comes to truck-mounted vacuum excavators, you also have the choice of a vac that is powered by the truck’s power take-off (PTO) or a self-contained system with its own motor. Your decision for this will likely come down to fuel costs. If you’re buying a small to midsize vacuum excavator, it is likely more economical for you to choose a vacuum excavator with its own motor. Plus, this setup offers the versatility to mount on new or used truck chassis or off-road crawl carriers. For larger vacs, a PTO is likely your only option, due to weight restrictions.

Time to decide

Armed with the right questions to ask and the correct order to ask them in, you should be all set to determine what vacuum excavator is right for your business. If you need any additional help, contact your local Vermeer dealer.

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