What CCTV drain inspection tells you about an underground asset

Underground drainage fails in ways that are invisible from the surface. A blockage that returns every few months, a section that surcharges in heavy rain, a slow leak undermining a pavement: the symptoms are visible, the cause usually is not.

CCTV inspection resolves that by putting a camera inside the asset and recording what is there.

What an inspection records

A CCTV inspection produces more than footage. The record covers:

• The location of the line and the position of features along it
• Depth of the asset
• Length of the run inspected
• Pipe type, diameter and material
• Condition, including cracking, displaced joints, root intrusion, deformation, scale, silt and debris
• Connections, junctions and unrecorded branches

That combination is what turns an inspection into a decision. Knowing a pipe is cracked matters less than knowing where the crack is, how deep the pipe sits, and what surface is above it.

Cleaning usually comes first

A camera cannot report on a wall it cannot see. Where a line carries silt, scale, grease or debris, drain cleaning is generally carried out first so the inspection assesses the pipe rather than the contents.

On many jobs the two are run together with a combination unit and a CCTV vehicle on the same visit: clean the line, inspect it, and report on the condition in one mobilisation rather than three.

Working with locating

Where the line itself is not accurately recorded, CCTV inspection and underground service locating complement each other. The camera confirms internal condition and alignment; locating equipment establishes the position and depth from the surface. Together they produce a record that can be marked up and worked to.

Common reasons for an inspection

• Investigating recurring blockages rather than repeatedly clearing them
• Proving the condition of an asset before accepting responsibility for it
• Pre-handover and defects liability inspections on new drainage
• Confirming the condition of existing drainage before construction above or beside it
• Locating an unrecorded connection or branch
• Establishing evidence for a repair, relining or replacement decision
• Post-repair verification that a rectification has actually worked

When the answer is excavation

Where an inspection identifies a fault that needs physical access, hydro excavation can expose the pipe at the identified position without damaging it or the services around it. Working from an accurate location and depth means a smaller excavation and less reinstatement.

This is the sequence Dynamic runs regularly: clean, inspect, locate, expose, repair, reinstate. Each step is informed by the one before it.

How the inspection is carried out

The method depends on the asset. A self-propelled crawler camera suits larger diameter drainage and sewer lines, where it can travel the length of a run and pan and tilt to look properly at a joint or a fault. A push rod camera suits smaller diameters and shorter runs, including property connections and stormwater outlets.

Access is normally through existing pits, manholes and inspection openings. Where no access point exists one has to be created, and that is where non-destructive excavation is used to reach the line without damaging it or anything around it.

What you receive afterwards

• Video footage of the inspected run
• A written report identifying faults and their position along the line
• Depth and alignment information for the asset
• Still images of significant defects
• Recommendations on cleaning, repair or further investigation where required

Reporting matters more than most clients expect. A report that positions a defect accurately along a run lets a repair be priced and excavated in one place. Footage with no positional reference usually leads to a second visit.

Inspection as a maintenance programme

Inspection is also used preventatively rather than only after a failure. On a network of any size, a rolling programme of cleaning and inspection spreads the cost, identifies deterioration before it becomes a collapse, and builds a condition record that can be used to prioritise renewal work.

For asset owners that record has value well beyond the individual repair. Knowing which sections of a network are sound and which are deteriorating is what turns maintenance from reactive spending into a programme that can be budgeted.

Where drainage runs under a road, a rail corridor or a building, the cost of a failure is set by what sits above the pipe rather than by the pipe itself. Those are usually the assets worth inspecting first.

Arranging an inspection

CCTV pipe inspections are available across the Queensland and New South Wales regions Dynamic services. Request a project quote or contact us with the asset details.