I have a 2003 Toyota Camry which on at least 3 occassions has a leak under the front passenger seat & floorboard in the rear rt side. It occurs about every 5-6 wks. Not a leaking gasket around door. What is causing this & what can a DIY spouse do?
It could be plugged drains in the door. Look along the bottom edge of the door for holes, usually square and make sure they are open to let water out that leaks in around the windows.
I would also add that it could be plugged drain for the A/C or the air intake area in front of the windscreen. Do you notice it after using the A/C for a while or after a rain/carwash?