I have spoken to the people who have done the CCTV survey. Before the survey they pressure-washed the pipe. As a result, water was pushed outside the pipe through the holes. They explained that what we are seeing in the video is the pressure pumped water coming back from outside the pipe...
Hi,
I own a terraced house (ca 1920) in North West London. I recently ran an inspection (the pipe was clogged) of the drain running under the house from the street to the back.
It turns out that there is water ingress. Water is actually leaking into the drain pipe from the surrounding ground...