If the car has a sun roof then the problem may be due to the drain tubes being blocked in the gutter area in which the sun roof sits. You may be able to clear these with some flexiplastic wire but take care not to push too hard as sometimes the metal drain tubes are linked to a plastic tube.
Other reason may be that the water is comming in through a door trim pad seal membrane. These sit behind the door trim pad (clipped/screwedto the door) Often after an accident repair to a door these are damaged and let water through from the outside via the door drop glass. Go to any body repair shop and they should sell you a replacement for a few pence.
Maurice, March 2009
