Water Flowing in pipes

Hi, so I'm back with my small puzzle pipe game. The client really want to see the water flowing in the pipes. He even gave me this https://www.youtube.com/watch?v=GdwY4W0Dgv4 for example. Right now it's looking like this :

and I guess He wants it like this :

What would be the better option to do it. The game is running one a very small computer so no liquid simulation I guess. I thought about doing some animations with plane but it would take forever to implement the fact that the water need to fall if there's no pipe at the end of the pipe that contain the water.