Same problem happened to me. Turned out to be the gasket on the power antenna. Put silicon between gasket and car, tightened antenna then cleaned off excess. Problem solved.
Hopefully, some of you will have this simple fix.

BTW, the compartment under the antenna filled up before the compartment for the spare tire did.

Tote

 

Has anyone tried messing with the sunroof drain tubes?

 

Draino. Pour some in from the sunroof into holes on both sides. Let sit 10 to 15 mins, flush with hot water- not boiling, until you see the water running under the car.

 

I’ve heard of running a snake through them but not something like Drano

 

Mine was a combo of weather strip and silicone sealing the trip piece above the seal underneath the window. water would get in that way.