Ford Fiesta liquid inside doors

Thought I was going mad but for awhile I've heard water or something moving inside the front passenger side door. Today when I opened the door I saw water on the inside rim around the door, on touching the seal at the botton around the door water, I presume, began to drip out at a steady rate. On checking other doors I found the rear drivers side door did the same. Could this be rainwater getting in the door somehwere and collecting inside the door or ar there any pipes that run through the door?