i noticed today that after driving to work my passenger floor inbetween the door and cat hump was wet. i know it's not the heater core because it's not antifreeze...it's just plain water. also, it's only wet under the floor mat...the top is dry. it doesn't look like there is any water coming in from the passenger window and it's not wet where the floor starts the incline towards the fire wall. all of this leads me to believe that there may be some sort of drain plug for water under there but i haven't had a chance to pull the carpet or get the car on a lift to see. anyone have any ideas?

well if it's only during rain, it's rainwater. That could come in through the ttops (if you have em) or the window. I guess you could have a rusted out floor but you'd probably notice that.