2001 Acura Integra 2001 Acura Integra water in hatch

Hi, I have noticed that whenever I drive in the rain, a significant amount of water builds up in the bottom of the hatch where the spare tire is. It is a problem because the car starts to smell funky and the windows fog up until I can pull out the shop vac and get the water out.
I have explored every possible option I can think of to explain this, but I cannot figure out why this happens. The water is not leaking from the hatch door, or from above the carpeting, because there are no visible leaks and nothing else gets wet. I checked the wheel wells but there aren't any holes. I thought it could be coming in from under the spare tire bracket, so I cauked it with silicone, but the water reappeared the next time I drove in the rain. Can anyone tell me what might be happening?