Hello, I am John, a Ford dealer technician.
I hope I can help solve your problem quickly and accurately.
It sounds like you possibly have a bad heater core. Unfortunately to replace this you will have to remove the dash to get access to it. To be sure check the coolant level in the engine compartment. If it is low this IS your problem.
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This is still a possibility because there is a vent that goes under the carpet to warm the rear of the interior. You need to check that coolant level and also smell the water you are sopping up. If it smell sweet like antifreeze this is your problem. If the water level is ok and this is definatly regular water then you have a water leak. Check that all the body plugs underneath are in place and all the door gaskets are in good shape. If you still can't find the water leak I would suggest going to this website. www.waterdoctors.com This is a service many dealers use to repair water leaks and there should be a franchise near you. You just call them and they come to you. If anybody could find a water leak these guys can! If a franchise isn't very local call the closest one, some of these guys travel 300-400 miles, they just schedule all their work in your area for one day.