1998 Chrysler Town and Country leaking water

Hi, My town and country starting leaking into the passanger side front floor. Whenever it rains out when I get home the rug is completely soaked, it does not get wet when I go through the car wash or if I hit a large puddle it seems to only happen after a heavy rain. I have taken it to the dealer and they can not find the reason why this is happening. Any thoughts on what could be causing this.