2000 M Roadster Leak - PLEASE HELP

I hope somebody in this forum will be able to help me. The car is in serious need of help. It's a 2000 M Roadster, and there is CONSTANTLY water saturated in the carpet under/behind the passengers seat. The car hasn't been in rain in weeks, but the carpet is still soaked. Based on this I am assuming that there is a resevoir of water somewhere that has collected from rain, and it just leaks slowly into the car. Has anyone encountered this before? PLEASE HELP ME!

The ac drains are plugged allowing condensation to build up in the heater case and drain onto the floor. The drains are above the trans underneath the car.

Hi yes you have 2 other drains one in a gas tank acces outside .and one from the roof behing the seat acces by the trunk