My Celica leaks water from the hatch or tail lights!!

I was hooking up my amps and subwoofer and had all the plastic interior panels out of the car and noticed there was water pooled in the seat part of the back seat, spare tire area, and the rear part of the body in between the tail light and the end of the small side window. There was a good amount of water in the spare tire area and the rear body. I sat inside the car and had my friend spray water into the cracks of the hatch and tail light but didn't notice any water leaking in. Is it possible water is coming up from below the car? The rubber seal looks good all the way around no rips or tears or cracks, I'm really confused as to where it's coming in from. The weatherstrip seal is $83 online, I just want to be sure it will get fixed because I don't want it to rust through the body to the outside, taking the panels off and vacuuming it each time rains would be lame. Thank you