Closed-circuit television drain inspections

Because drains are largely hidden from view, the exact cause and nature of problems may not be immediately apparent. With the passage of time and usage, drains can deteriorate. It may take several years but drains can suffer as a result of many factors such as ground movement, construction defects and tree root invasion.

Closed-circuit television (CCTV) surveys of drains, pipes and sewers provide accurate and cost effective ways to detect problems and help establish the most practical options for repair. This involves using a special camera to view inside the pipe to locate any problems.

A CCTV inspection can be carried out with the minimum of fuss and disruption.

The CCTV camera is inserted into the drain via a manhole or appropriate access point and pushed or powered through the pipe. As the camera travels along the pipe, the image is relayed to a monitor screen above ground. The operator will then log any structural defects and record the location of each defect along the pipe length.

A survey report is then provided which lists the type and location of any defects. This can be backed up with photographs or video records together with a site plan showing the drains location.

Common faults revealed by CCTV       

Cause     

Consequences

Tree roots in drains

Roots seeking moisture  

Materials flowing through the drain will snag on the roots causing continual blockages. Roots dislodge or crack the drain, resulting in leakage and further damage 

Fractured pipe

Pressure above ground

Cracks or fractures in drains leak water which destabilises the surrounding soil. This will result in further damage to the drain and even subsidence to buildings nearby

Collapsed drain

Several possible causes

Drain becomes unusable with high likelihood of frequent blockages, environmental damage and building subsidence