Getting rained on in rear storage area

We have been getting a few showers here and there and I have just been running my bikini top getting the rear cargo area wet. Long story short, I kept noticing the rear tie downs right next to the tailgate in each corner were wet and I thought they were wet from the rain but noticed everywhere else was dry. So I pulled up the tray above the jack and sure enough it was full of water. I felt pretty dumb at the moment and alway wondered where the jack was hid on the thing. I noticed there is a plug you can partially pull out so it will drain, but not let a lot dust flo. The plug may have a hole and was stopped up, but I didnt check since I was in a rush. Got a Tonneau cover, but it just funnels all the water behind the rear seats, so I guess you just dont win on that one.

Anyway, might save someone from having to wash out there tub if they're getting wet in the back too.