What is it?
It involves lowering a camera down a drain. From this, the picture is transmitted to a screen on the ground. This then shows whether there is damage to the drain or not.
Why do it?
The legislation have recently changed the rules on who is responsible for which bit of drain or sewer, so it's not a bad thing to have a survey which clearly shows what is where and whose is whose. Furthermore, it's good to know what state your drains are in as it can cause you and other people a lot of problems if blocked. If your property has been subject to extremes of weather there is an increased risk of subsidence which a CCTV survey will show up if the drains have moved and caused a fracture in the pipe.