Auto body repair & detailing: floor board water leakage, seam sealer, hose spray

Question
Make: Buick
Model: Lesabre (Custome)
Year: 2000

Problem:  While parked and raining water comes up through the seams of the floor board on the driver side back seat, the front driver/passenger side and passenger rear remain dry.  I have used a water hose and sprayed the back of the car with no water seaping in.  It appears to come in when the water draines down the top or front windshield.  How would I correct this problem?  

Answer
With a water hose spray small Areas of vehicle until you locate the source of the leak then mark area with tape and let dry. Then take some seam sealer or silicone to seal the leak let the seam sealer or silicone dry. after it is dry check with hose again. Repeat as necessary. If it is leaking from under the windshield you may have to take off the windshield mouldings. If it is very rusty around the windshield the glass people will not reseal your windshield. Because it is a structural part of your car. Hope this helps.
               Thank you for the ?
               Ken