Ok, I installed aftermarket AC in my car and after few days I was shocked to see water under the carpet. I tried many mechanics including the one who installed it. Sometimes water drops on the feet of passenger and sometimes water was found under the carpet. It is really a pain for you. Let me say how I resolved this issue.
The AC compartment installed inside the cabin, I suppose called condenser. On the floor of its cover there was a flat sheet which was not leveled and it was not fully allowing water to flow towards drain. Cool water stays there and when water level rises here, some of the water flows towards drain pipe, so a quantity of water remains there creating drops of water on outer side of the plastic cover which fells on passenger feet. I opened this compartment and pulled out the floor sheet and leveled it properly. It only solves one issue. Water was still collecting under the carpet.
I noticed that the genuine rubber on the hole where cool pipe of AC enters in condenser was not installed by the mechanic. There was no insulation on this one inch part of the pipe where it enters from the engine bay and the pipe was touching body. Water droplets were using this exact place where pipe is touching body and from here these droplet travel towards car carpet. It was not possible for me to little bit bend this pipe from here so that it could not touch body. So I took piece of insulating pipe, applied glue inside it and put this insulation pipe on that area. Now AC pipe is still touching the body, but water don't fell inside cabin as insulating pipe has glue in it.
I hope you can also have a detail study of water paths and can found somewhat similar to my story.
Regards.
