I bet I know where its coming from but you'd have to come to me for me to fix it.

Here are some things to fix though while your at it yourself...pull out both front seats and pull back carpet. All the round drain plug things need to be reglued over. This goes for the round plugs along the where the door closes too that sit vertical. Some are covered up by the wiring harness that run on the driver side but there are holes on both sides. Also, where the plastic parts that clip in by the door and hold the carpet, where they actually clip in to needs to get sealed well. Once all those spots are sealed your leaks should stop.