Bought a 1999 accord couple of weeks ago and it is parked outside in the open. Three days ago there was some serious rainfall and I found water (quite a bit actually) on the front passenger's side floor. I saw on YouTube that with age, the plastic sunroof drain pipe shrinks and pulls out of the exit tube in these cars, so I checked. I opened the sunroof and poured water into the tracks. Sure enough, water leaked into the front passenger side floor, whereas in the other three corners of the sunroof, the water drained out to the pavement. But I don't understand one thing. During the rainstorm, the sunroof was closed tightly shut. As far as I can tell the sunroof itself does not leak. So how can water be coming in to the passenger side floor through the sunroof drain, even during a rainstorm, if the sunroof is shut? Is there some other place through which rainwater can get into the passenger side floor? Perhaps through the cowling at the base of the windshield? Just trying to figure out where the water might be coming from so that I can attempt a repair.
thanks in advance for replies.

 

Have a look at the windshield corners near the top

 

front windshield seal possible leak.