Hydrovac Excavation – The process – Benefits and Applications

Saad Iqbal | 🗓️Modified: October 4, 2018 | ⏳Time to read:8 min

So you are stuck in a situation when you have to decide between mechanical excavation and soft excavation by hydrovac; so here I am to tell when would you need a hydrovac ? Alongside, we’ll go deep into process, benefits, and applications of hydrovac excavation.

If you are client or owner of the project who are not familiar with this type of excavation technique and wondering what is hydrovac excavation? or how hydro excavating works? So this article will explain everything you should know about hydrovac before opting.

Gone are the days when you can dig anything out of the ground that surrounds within jurisdiction of your land. Locating the underground utilities and a need for an undisturbed excavation is a major requirement while planning for any type of construction or renovation projects.

A one single mistake and a wrong dug hole could lead to a thousand dollars damage and an environmental misfortune. So you are lucky that you have arrived on this article and keep reading to know about; when would you need a hydrovac excavation?

Hydrovac Excavation
Hydrovac Excavation

What is hydrovac excavation?

By definition it is an alternate to mechanical excavation which involves the usage of heavy duty excavators and tractors. It is comparatively a new form of digging that uses super-pressurized hydro jets for breaking down the stiff soils making excavation an easier task in areas where conventional or traditional excavation (mechanical excavation) is a hard task to execute.

Pro Tip

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Hydrovac excavation was introduced back before 1960s but still its application is not that common despite of so many benefits.

The mechanical excavation always has a problem of damaging the buried utility pipelines and conduits thus creating havoc for the client. In such situations, Hydro Excavation – an advance and modern approach would do the rescue as it is a non-destructive digging process.

So, it utilizes both pressurized water and a power vacuum system that can safely and quickly uncover the utilities and infrastructures underground.

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How Hydrovac excavating Works?

Hydrovac excavation also sometimes termed as hydro excavation and is carried out with the help of a hydrovac truck or trailer. The truck is used for inserting the water wand into the ground that is supposed to be excavated.

The working principle of hydrovac is liquefaction of ground soil i.e. it liquefies the soil by injection of water creating a slurry mix that is vacuumed afterwards. Due to this, it is also termed as vacuum excavation system.

After that the ground is eased up after passage of high pressure hydro jets. This slushy mixture of soil and water is then sucked through a vacuum hose which is afterwards collected in a storage tank attached to the hydrovac truck.

Hydrovac trucks come in two types of arrangements one can have a positive displacement blower (rotary blower) or a fan system. A rotary blower uses the positive displacement technology by trapping a certain volume of air then discharge or forcing it out against the system pressure.

The other type of hydrovac trucks come with fan system. The later one is able to handle large amount of air and thus can do excavation at faster rates than the ones with rotary blower. They are also easier to operate and are less expansive as well.


 Application of Hydrovac Excavation

It can be used in any type of soils even in frozen ground. Hydrovac can be used to dig up to depth of 70 feet and can reach long distances. This type of vacuum excavation is proved as a soft technology and is proved as best choice for areas in the vicinity of underground excavation.

Hydrovac works efficiently in any type of material that needs to be dug up on a construction site for example, hard-packed clay, gravel, sand and even ice.

Situations when would you Need a Hydrovac

The following are some of the benefits and advantages of hydrovac excavation and these are the reasons why hydrovac surpass the traditional method of excavation.

When it comes to an excavation work for a mega project, it takes up a major share of the time schedule before the actual construction work could commence. So the use of hydrovac could ease-up your worries as in that case you don’t need to employ hundreds of excavators and manual manpower, you could easily manage the contaminated materials speeding up your excavation projects.

When would you need a hydrovac
When would you need a hydrovac

1.     Spotting Utility Lines

Among all the situations that require hydro excavation, this is the most significant situation. I still remember when I was working on a road project and despite the fact that locates for gas pipe line was already done but still just because of a small negligence of the excavator’s operator that gas pipe line was ruptured and resultantly the supply to the domestic and industrial users was cut off, we had our work stopped for almost 3 days and a fine was imposed on us.

This is not only one incident, there are so many more being witnessed in mega construction works. This process of searching, finding and locating the underground utilities while excavating the site is sometimes referred as potholing or daylighting. A test hole is dug to locate the underground infrastructure utilities like gas line, water pipe lines, sewerage lines etc.

So if your construction is in developed, populated zones where there are so many utilities; so it is best for you to opt hydrovac. Because if you opt conventional digging, besides hitting the buried power lines, you could actually be destructing the surrounding soils and creating a mess for others.


Using this new technology of excavation, you could not only be less destructive on the soil but you are actually saving your time and money that is otherwise spent on repair works.

So it can be said that in congested areas where there are potential underground utility lines and you are bound to avoid disturbing the surrounding soils then that is the situation when you need a hydrovac.

2.     Excavation in cold weather is made easy

Well while living in colder regions such as Canada, you better know how difficult it is to dig the frozen soil; so in such situations hydrovac is for your rescue. This difficulty is associated with the ice that hardens the ground. But as you can easily use pressurized stream of heated waters you can easily loose up the icy cold grounds.

3.     Draining Excess Waters

Hydrovac vehicles are well suited to dealing with an abundance of quickly melting icy waters. Alongside working to drain large pools of water in parking lots, the hydrovac trucks in Saskatoon worked to clear drains that remove water from roofs to prevent further collapses and leaks.

4.     Digging Pile Holes or Slot Trenching

Yes! You can dig holes with hydrovac in half the amount required by traditional methods. Making a quick and effective excavation in cold climates is cost effective for pile holes, whether these holes are for supporting utility poles or end-bearing piles. You’re capable of getting more done in half the amount of time.

Slot trenching is the process of digging slim lines into the ground in order to install pipes, cables, and other such underground utilities. Vacuum excavation contractors are preferred over mechanical contractors since it reduces the risk of damaging existing underground facilities.

5.     Debris Collection

Mechanical excavation generally does not allow for debris collection. Due to this, debris is placed at the side to be collected at a later date. With Hydrovac excavation, however, the debris is collected adequately, and is disposed of in a suitable manner, since the debris is collected in the attached storage tank. And, this helps to dispose of the debris as you please.



FAQs about Hydrovac Excavation

Do you need Locates in case of hydrovac excavation?   

Now this is a very common question as there is a misconception that prevails among the masses i.e. you don’t need locates while excavating by hydrovac. But let me tell you that even soft excavation is a proven safe digging method but even then you can’t ignore the need of locates.

In most of the countries including Canada as explained by citywindsor; before any digging or excavation can take place, you must notify all utility companies so that they can locate and mark their underground utility. There are certain companies that would help you in arranging locate like Ontario one call.

Call before you dig – It’s the law J


Saad Iqbal is a professional civil engineering and freelance write. He's passionate about structures, construction management, and home improvement topics. He's been working as a Senior Engineer in a consultant firm for over 8 years. Besides he loves writing informative and in-depth content focused on construction and home-related topics. You can catch him at his linkedin page or reach out via our contact us page.

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1 thought on “Hydrovac Excavation – The process – Benefits and Applications”

  1. Hi there! When you said that we can even conduct hydrovac excavation to get rid of debris, it really captured my attention. One of my neighbors just completed her home renovation last week and wants to clean her backyard. I’ll ask her to consider this option so the process can be done swiftly later.


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