The car has always been well maintained. However, about 2yrs ago water started to accumulate in the rear foot well on the pass side. the water comes weather rain or shine. about every four months the water will accumulate. It is always in the rear pass foot well.
2006 LINCOLN TOWNCAR LEAKS WATER INTO THE PASS COMPARTMENT ON PASSENGER SIDE on 2006 Lincoln Town Car
check to see if your drain tube is plugged for the a/c
Check out "How to fix a water leak on a lincoln town car" on youtube. It's how I fixed my 98 lincoln Cartier Town Car. It's the cowl under the vent grate at the back of wall of car where the air comes into the car. The gasket gets old and worn out. I cleaned off old and went to the hardware store Menards or whatever you have avilable. I used a silicone base sealer in a tube for weather/water proofing your windows on your house or around tub, I used Black. Its just a little messy. I also had my neighbor to blow out my A/C lines to see if they were plugged, they were not. The only other thing is it could be heater core but if you get good or great heat and cool A/c, It's the gasket issue I had an issue with. It will take more time to clean up the water in the passenger side then to fix it. Cost of fix around $5.00