Non Destructive Digging Basics
What is hydro excavation?
Hydro excavation is a non-destructive digging (NDD) method that uses high-pressure water to break up soil and a vacuum system to remove the slurry. It’s ideal for safely exposing underground utilities without causing damage.
Where is hydro excavation used?
Common applications include:
Locating underground pipes, cables, and fibre optics (potholing/daylighting)
Digging trenches for utilities
Excavating around tree roots
Pit and drain cleaning
Sign post and pole installation
Service location for roadworks and civil projects
Why is it safer than traditional digging?
Because it uses water instead of mechanical digging tools, there’s far less risk of striking and damaging underground infrastructure like gas mains, water pipes, or power cables.
How deep can hydro excavation go?
Depth depends on the equipment, soil type, and access. Most Melbourne hydro vac trucks can dig up to 3–5 metres deep safely, and further if specialised long-reach gear is used.
What types of soil can be excavated?
Hydro excavation works on clay, sand, gravel, and compacted earth. In very hard or frozen ground, hot water hydro excavation may be used to speed up the process.
How is the removed material disposed of?
The excavated slurry is stored in the truck’s debris tank. It’s then transported to an EPA-approved disposal facility or a designated site that meets environmental regulations.
Is hydro excavation affected by weather?
It’s less affected by rain compared to dry digging methods, but extreme weather (heat or storms) can limit safe operation. Cold climates sometimes require heated water.
How much does hydro excavation cost in Melbourne?
Rates vary depending on truck size, depth, material, and job location, but typical hire rates are:
$220 – $350/hour for standard hydro vac trucks
$180 – $250/hour for smaller units or half-day minimums
Some companies charge a call-out fee for short jobs.
Do I need permits for hydro excavation?
If the work is on public land or near council assets (roads, footpaths), a council permit and traffic management plan may be required. Providers often handle this for you.
What’s the difference between hydro excavation and vacuum excavation?
They’re essentially the same process. “Vacuum excavation” focuses on the suction part of the job, while “hydro excavation” highlights the use of water to break up soil.
Can it be used near tree roots without damage?
Yes — hydro excavation can expose roots without cutting or tearing them, making it ideal for arborist and tree preservation work.
How long does it take?
A small pothole might take 15–30 minutes, while larger trenching projects can take hours or days depending on length and depth.