1990 Honda Accord Q&A
1990 Honda Accord Question: Water getting into the trunk
Its best to look for water leaks when the car is dry. Pull out the carpet, get in the trunk with a flashlight, get a friend to spray water from a garden hose around the circumference of the trunk lid, windscreen and tail lamps. Check closely the trunk seal. - patrick mannion
Check for possible corrosion from below. Check body seams for possible leaks. - DaveJHM
for me the rain is getting in through my back lights, I've heard you can get a new tail light assembly, but haven't done it myself. - Nirat
Leaking gaskets around the tail lights can allow water entry into the tail light assembly. New gaskets should fix this concern.