Comparing Vacuum Excavation to Hydro Excavation

As the premier supplier of Vac Ex services in the UK, you’ll often find us educating about suction/vacuum excavation, but many people don’t realise that vac-ex can also be utilised via a water-based approach. This water-based approach is widely known in the industry as hydro excavation and is another excellent alternative compared to the traditional manual digging excavation. It’s important to understand the pros and cons of each excavation method and why each form of excavation should be deployed for the best possible outcomes.

Understanding vacuum excavation

Compressed air is used as a source of energy to penetrate, loosen, and agitate the ground. The debris is then sucked up by the force of the vacuum and collected in a sealed tank onboard the vac ex machinery.

Understanding hydro excavation

Instead of a jet of air, hydro excavation combines a vacuum with high-pressure water to loosen and reduce the strength of soil, making it easy to vacuum out of the area using the vacuum/suction method described above. As high-pressure water is more aggressive than air, it can cut through more stubborn, difficult ground. The water is delivered via a reservoir tank that’s usually mounted on the excavation machinery. The use of pressurised water presents unique benefits, which makes it more suited to certain situations but also less suited to others.

Hydro Vs. Vacuum Excavation

Safety

Safety should always be the number 1 priority when it comes to excavation, minimising the risk of striking services at all costs. As underground utilities can be delicate, it is sensible to choose air over water when their presence is known or unknown. As air is a gas, it will compress and flow around a utility with less risk of damaging it compared to an aggressive, highly pressurised stream of water. Also, unlike water, air is not a conductor, which makes it safer to move soil away from underground electrical wires. Where there is a risk of chemical reaction with ground materials, vacuum excavation may also be the safer option.

Soil Condition

This is perhaps the biggest influencing factor when considering vacuum excavation or hydro excavation. When ground conditions are more difficult, with hard and compact dirt or rocks, a high pressure water approach has the edge as it is more effective at cutting through these stubborn ground types, saving time and man power. Vacuum excavation is better suited to excavating loosely compacted soil or sand.

The backfill

The excavated soil from vacuum excavation can be reused to fill in the hole when the work is completed, unlike with hydro excavation where the soil is wet so it is unusable resulting in having to take slurry material away and dispose of it and bringing dry soil in to replace it. Given the routine sequence of excavating, performing the work and then putting the ground materials back in place, the option of vacuum excavation is more viable.

Resources

The resources available to you for a project are a really important consideration. With vacuum excavation, compressors can generate a limitless supply of air, whereas with hydro, it requires a constant supply of water, which might not necessarily be available. Things like access and terrain may also limit what you can do and bring on to site.

Clean up

The clean up process is much quicker when using vacuum excavation as the excavated material can be reused for backfill so there’s less to remove or clean up. Water makes the site messier and adds a significant amount of time to clear up and remove waste.

The choice between vacuum excavation and hydro excavation

At John Mee Vac-Ex Hire we don’t see it as a competition between hydro and vacuum excavation, used effectively together, both these approaches can work well together to deliver safe and predictable excavation outcomes. As you can see from the above, each method has its own unique pros and cons that make choosing which to use more logical on a project by project basis.

Not sure if you need hydro excavation or vacuum excavation? We can help!

If it’s still not clear to you which excavation approach is the most suitable for your upcoming project then we’re happy to guide you further.  Our sales and service team at John Mee Vac-Ex Hire have decades of experience in vacuum excavation, being the original operators in the UK. Take advantage of this expertise with free advice when preparing for any job. Let’s get the project specified correctly, first time.

With our operated hire, our elite and accredited operators can tackle the most complex jobs with both vacuum excavation and hydro excavation and have delivered over 1 million working hours with zero strikes.

Speak to an expert today on: 01302 636 532

formed Editor at Vac-Ex

We have been in the business for more than 30 years and service customers across Lincolnshire and beyond.