barfo

For some reason after driving in the rain, water tends to collect in the left rear tail light assembly, and then drains through the light bulb connector. From the outside, I can't determine where water is finding it's inside the light assembly. I've compared it to my 1999 Accord, but still don't know where it's coming in from without removing it, which is what I'm planning on doing soon. I'm wondering if the seal gasket is going bad. Any quick thoughts?

Thanks!