Slit Trenching Process – The Advantages of Slit Trench Utility Investigations


Slit trench utility investigations are becoming more and more necessary for the modern construction industry.

They are now used for more than just locating underground utilities; they are also used to detect geological anomalies, and in some areas, people will use them to install pipework.

But wait, you might be wondering, what exactly is a “slit trench utility investigation”?

Well, for starters, slit trenching is a construction method or technique which involves digging narrow trenches to reveal or confirm underground utilities which are existing on-site. As I have mentioned, it is also used to install underground utilities such as pipes, cables, and conduits. Other items, such as footings, structures and traffic signs, can also be installed using slit trenching, but for that case, they’re not actually measuring the utilities or measuring depths, they are just avoiding them.

To give you a better picture, the process of a slit trench would be using the vacuum hose to suck out the ground soil and then install the pipe. Utility workers will generally do this in the city or a congested area, like the CBD or areas with critical assets such as high-pressure gas and high-voltage lines.

Slit Trench Services provided by Geoscope
Slit Trench Process using vacuum hose to suck the ground soil

The slit trench process is also becoming a key step in many construction projects because it can save construction time and money in the long run.

To provide more information, slit trenching can be performed in a variety of ways.

The first is to use traditional excavation methods but with minimal impact techniques, such as hydro excavationthese are typically preferred due to their non-mechanical, non-destructive, and more efficient operation.

On a lower budget scale, people use shovels and hand dig trenches, or we call it “manual excavation”, just as it sounds, people dig trenches with their blood, sweat, and tears and do the work manually.

Slit Trench Manual Digging Process
Traditional manual excavation digging process

Mechanical excavation is the last and least ideal method among the various types of slit trenching processes; it is the least and worst method because it involves an excavator, which has the highest risk and hazard in terms of uncovering underground utilities. 

Because they’re using excavators that weigh between two and sixteen tonnes — these are big, heavy, earth-moving machines that once you put the metal excavator bucket next to the gas pipe, there’s no turning back. You could cause accidental damage to the utilities underground which could cost you a fortune.

Mechanical Excavation Process using Excavator with Excavator bucket
Mechanical Excavation Process using Excavator with Excavator metal bucket

Well, people can say that they are just going to do it safely, but we never know, the next thing that could happen is unlikely, and it’s no longer safe, is it? That is why it is the least ideal and worst way to go about it.

However, there are always more benefits to conducting slit trench investigations than drawbacks. In fact, a slit trench utility investigation is an excellent way to gather the information needed to determine the best course of action for a construction project. In addition to the time and money-saving aspect that it can offer, there are many other game-changing advantages that it can offer you or anyone in the construction industry.

And here are the advantages of slit trenching utility investigations:

  • You get to see what’s exactly below
  • You get the right information, the first time
  • It can help you save time, save money, and make your work more efficient
  • It can help reduce rework and reduce stress for both utility locators and clients
  • It can help you verify if the utility locators did their job right or not 

Now that you have an idea of what the game-changing advantages of slit trench utility investigation are, let us go over them one by one.

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The Game-Changing Advantages of Slit Trench Utility Investigation

1. You get to see exactly what's below.

Slit Trench Utility Investigation Service provided by Geoscope
Using Slit Trench Utility Investigation, you'll see exactly what's below

Seeing is believing. 

When you choose the slit trenching route you are rewarded with a more complete picture of what’s below than localised potholing.

Simply because you’re opening a section of footpath or road, instead of just small little individual potholes, you will be able to see other utilities running parallel instead of chasing individual utilities. 

When you see utilities side by side, you can see the exact and verify the heights, locations and any potential clashes. 

When I talk about clashes, these might be what potential asset owners or civil designers would find when planning on introducing a new utility running in line with that slit trench. 

So, the slit trench is there for a purpose and our clients typically want to know what utilities are running along that proposed trenching line so they know what utilities are located below and their exact heights of them.

2. You get the right information, the first time.

Slit Trench Utility Process revealing the information right, service provided by Geoscope
Slit Trench Utility Investigation Process revealing the information right, the first time

One of the most significant advantages of the slit trench process utility investigations is the accuracy of the data that is obtained. 

Slit trenching provides an accurate and precise measurement of the location and depth of underground utilities as we get to view the data in a three-dimensional view of what’s lying underneath.

You can look down from above, you can look sideways, and you know exactly whether utilities are within the utility trench.

In short, you’d get a more complete perspective because potholing is an individual whole in a localised spot. Whereas a slit trench is a full trench and you can see what’s beside it. While in a pothole, you can’t see what’s beside it because you only see straight down.

3. It can help you save time, save money and make your work more efficient

Slit Trench Utility Investigation Service provided by Geoscope
Slit Trench Utility Investigation making work efficient

Slit trenching is a faster and safer way of digging. Since non-destructive digging or NDD is the most dependable method of safely removing earth and soil without endangering nearby objects and infrastructure such as underground telephone, gas, and electricity lines. 

NDD is also a quick and efficient process that enables operators to quickly locate utility lines in the event of a tight schedule or an emergency. Its speed and precision also make it a cost-effective option in most appropriate applications, and these are massive advantages for any project out there. 

Non-destructive method used to locate underground utilities service provided by Geoscope
Non-destructive method used locate underground utilities

To tell you a bit more about it, slit trenching investigations for utility locating are one of the best options if you want to save time for the efficiency of your project and save money from damaging underground assets. 

For other construction industries, slit trench processes are very common in areas where there is a lot of natural rock below the surface. 


Using a method that does not damage hard objects or surfaces, the construction workers can dig right down to the rock surface without having to dig down too far and risk damaging the rock. 

This is actually a major advantage to construction companies as well, because they can use the rock as a natural means of supporting the structure of the building. This way they will be able to avoid digging through and damaging rocks with mechanical breakers that will not support the structure.

4. It can help reduce rework and reduce stress for both utility locators and clients

Slit Trenching Process service provided by Geoscope
Slit Trenching Process helping reduce rework and stress on the project

Since we have mentioned already that we get the information we need the first time by using the slit trenching process, it would also mean less rework and less stress on-site and that is basically good news not only for the utility locators but especially for the clients and civil construction crews who want to get things done in time.

Less rework also means fewer times that the utility locators need to come back to the site to mark it out again. I mean, why locate something that has been completely captured right the first time?

Environmentally wise, the fewer times everyone needs to come back and touch the site in some way, the less time the client needs to keep digging and to keep verifying the underground utilities. A sustainably positive result.

The less waste all around will continue from knowing what’s below. 

Waste Management as a result of Slit Trenching Process
Sample soil waste produced by slit trenching process

It will positively impact the client’s project because slit trench utility investigation has the potential to save them from the uncertainty of what’s really below their work site.

Using this method will guarantee that they will have confidence and an in-depth understanding of what’s within their work area. 

This can also benefit on cost-effectiveness for the clients’ side since returning to work would mean extra costs, especially for the return visits and manpower labour, but also the minimising transport of soil slurry to the waste management facilities.

5. Verify the utility locating survey accuracy

Slit Trenching Process Service provided by Geoscope
Slit Trenching Process verifying locating survey accuracy

Not many people are aware of this but the slit trench technique or process can serve as the verifying process of what utility locators marked on the subsurface are really what’s below the ground. Compared to the potholing method, even if done right, you can only come close to the truth of what’s really underlying below, but with slit trenching you will be able to get a clear picture of what type of utility assets are present below.

You see, using this method can pretty much confirm whether you have engaged a professional utility locator who did his job right or not. 


When you hire professional utility locators like Geoscope, who strive to deliver blue-ribbon services for our clients and the construction community, you’ll see the difference when the utilities are verified in real life.

There you go mate, you now understand the game-changing benefits of using slit trench utility investigations.

To give you some bonus information, if you are wondering whether every project requires slit trenching,

Does every project require slit trenching?

Slit Trench Utility Investigation Project Overview and Evaluation by Geoscope
Project being evaluated whether it needs Slit Trench Utility Investigations or not

Then my answer would be no, it depends. Not every project requires a slit trench process, some people just settle for doing individual potholes to verify individual utilities below, but if you really want to get the full picture of a cross-section of what’s underground and you want to get the information right the first time and avoid project rework then slit trench utility investigation is for you.

Also, if you are puzzled about when to perform this kind of method …

When to perform the slit trench potholing method?

Slit Trench Utility Investigation Services provided by Geoscope
Slit Trench Potholing Process being performed prior to main groundwork

Well, for those who are unfamiliar with this process, it is typically performed prior to the main groundwork or construction work. This process is more suited to designers since utility clashes affect professionals who are designing and planning, as well as guys who want to know exactly where the utilities are. So, it all comes down to the process’s design stage. 

This method is generally done on the night shift if it’s a busy road, if it is not a busy road or out in rural areas, then potentially we could complete these works during the day. 

But if your question is how to go about this process?

How to go about the slit trench utility investigation?

First, you need council approvals before beginning any work because employing the slit trench process is not that easy, especially if it is in a residential area, then you need to do letterbox drops to put a letter in everyone’s mailbox to let them know that there’s going to be potential impactful work in the area. 

Slit Trench Utility Investigation Services in Sydney provided by Geoscope
NDD Slit trenching Process by Geoscope

You need to do this first because this process can be challenging in a noise-sensitive environment. There are jackhammers, and concrete saws, have you heard of them being used on-site before? Whether you have or haven’t heard them before, you don’t want to hear them because they’re very loud engines and the high-pitched noise when cutting the concrete. Ugh. You might have a problem with the people around concerning the noise. 

The next thing you should do is to familiarise yourself with the laws concerning underground utilities. 

One major act of the legislation is communicated in Telstra’s Duty of Care statement. That’s a requirement by law and it’s under Safework Australia or Safework New South Wales. It basically says there that if you damage communication cables, you will be held responsible and there is potential for fines or even jail if you are proven guilty of intentionally damaging communication cables.

Slit trenching process performed to reveal Telstra cable utilities service provided by Geoscope
Slit trenching method used to reveal communications cable underground

Also, according to the Safe Work Act, if you’re digging unsafely, there’s the potential to put people at harm by exploding gas pipes or hitting electrical cables, and you will again, be responsible and have to pay for the damages you caused. If you want to know what to do when you cause Accidental Damage to underground utilities, please refer to this article below.

Accidental Damage to Underground Utilities

Did you know that damage to underground services could easily take place on your site? What’s the worst that could happen? Accidental or not, damage can ...

This is also the reason why non-destructive digging is the go-to option if you want to avoid accidental damage to underground assets.

Non-destructive slit trenching potholing service provided by Geoscope
Non-destructive slit trenching potholing service provided by Geoscope

But don’t stress yourself much about it, I get it, the process can be a lot to go about alone, and that is why Geoscope is here to help you. 

If you really want to know more about how to go about this process from start to finish, you can just give us a call and we can provide you with full guidance and assistance in terms of everything you need to know about the process so you do not have to worry about anything.


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