After heavy rains my driver side floor board is soaked. I am not talking hurricane force rain but slow and steady for hours.

96 C280 had the problem when I was on an incline but seems dry today after several hours. Parked on level surface.

01 E320 sat no more than two or three hours and passenger side behind driver has a few gallons of water sitting.

2X on different cars - is this a known problem with MB?