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When Is Drain Excavation Necessary?

The short answer to that question is – when you have absolutely no other option! Drain excavation is a complex task, needs careful safety monitoring and can be costly, so it should be used only as a last resort and only if the drainage problem is so severe that other methods are not feasible or have failed.

What is drainage excavation and why would you need it?

Drain excavation involves physically digging a hole or trench to the drainage in need of attention, with the possibility of damaging whatever is above the problem area. Sometimes a drainage problem is so severe that it really isn’t possible to fix it without digging right down to it. The drain might be old and in poor condition, with multiple leaks, or may have collapsed altogether. Even if it isn’t old, it could have been severely damaged or may have suffered from subsidence or flooding, it could also be completely blocked by tree roots.

How is it done?

There are a number of elements to a professional drain excavation job besides the actual excavation and repair work, including site assessment, health and safety considerations, storage of the excavated material and site reinstatement.

Site assessment

The last thing you want to do – as already mentioned – is dig a hole when you don’t actually have to. Having established that it’s unavoidable, you don’t want to dig it in the wrong place. Correct pre-excavation diagnosis and knowledge of the exact location of the problem is essential to planning cost-effective and efficient repairs. Additionally, drainage pipes are often in close proximity to other services such as gas, electricity and water, so these need to be located and included in your plan.


Trench work can be dangerous, both for the workers and any passers-by. Besides the various service connections mentioned above, there’s always a risk of subsidence if the ground is unstable and frequently wet. The deeper the trench, the worse these problems generally become, and for big excavations it’s essential to incorporate correct shoring mechanisms and barriers.


Although there are mini excavators available, digging by hand is generally the safest and least disruptive method of excavation, particularly when there are pipes carrying other services in the area.


If the excavated material can be used for backfilling, space needs to be made or found to store it safely and keep it dry, and if not the material must be disposed of responsibly.


The details of the post-repair reinstatement of the site would have formed part of the initial plan. The trench must be filled in such a manner that there won’t be later subsidence, while concrete, tiles and poles should be replaced in a “like for like” manner.

At 1st Call Drain Clearance we have many years of experience in all aspects of drainage, including full excavations. We have the know-how, equipment and personnel to assist you with any drainage problems you have with minimum disruption. If you really do need excavation – or would like to discuss any of your drainage problems or requirements, call us!

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Areas We Cover

We have engineers covering London, Central London and the Home Counties


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