Large amounts of water in Trunk!

Ive been having issues of water getting into my trunk. I bought the car a year ago and it had 92-93 tail lights. About a month or so i bought 90-91 tail lights from some guy parting his car out and i put those in. Ive noticed that my tail lights have water in them as well. if you see closely the picture shows how theres water on the very bottom inside the tail lights. When i had the first pair of tail lights it wasnt raining so i never got a chance to see if they leaked water inside. Both the left and right side of my car behind the interior panels are wet. Im not sure if the tail lights are causing me to have water or if it has to do with the hatch itself. How would i be able to differentiate between the two? Thank you!

If you have a sunroof, the drain tubes (located in each side of the rear quarter panel) are very prone to leaks.

As well as the tail light gaskets.

You can put some old towels around the outside of the trunk (or anything else that absorbs water), and the ones that get wet will help pinpoint the leak.

If you replaced the taillights w/o new gaskets, leaks are likely, but I am not sure if they can account for all the water in your pics.

The drains are on either side of the trunk behind the plastic trim, and they can get clogged, or disconnected from the plastic elbows that connect them to the outside, under the rear bumper.