I've been watching videos about different types of basement drainage systems. In this video, the guy describes how (in his opinion - I'm no expert) groundwater will bypass a traditional French drain. Their system, which is installed much lower under the floor, is superior. In this still picture their diagram shows a large plastic pipe (about 8" in diameter) being installed on a bed of small stones.
The video is quite convincing. He describes the "cold joint" between the footing and the wall and how water will seep through it. It is plain to see that the French drain sits above this level and would not control the water, but their system would. In any case, my question is how does the water get into that black pipe? It doesn't appear to be perforated at all. I know one end terminates in a sump pump, but couldn't water only enter the pipe at its far end? Confused!
Here is the video. My screen grab is from 1:46.