There are many different threads in this forum about water leaking into the boot but this one in specific is for water welled on top of the boot parcel shelf.
In my case the root cause of the problem was the third brake light. It had a small gap where water leaked in and after I filled it with silicone the problem was fixed.
Simply pop-out the rubber caps in the inside of the boot door and press the third brake light out (by pressing the two latches on each side of it), fill the edge with silicone and put back in place. I suppose replacing the bulb when it goes off will be tricky, but we'll see. I hope this helps.
Here are a couple of pictures of mine before I filled gap with silicone.
In my case the root cause of the problem was the third brake light. It had a small gap where water leaked in and after I filled it with silicone the problem was fixed.
Simply pop-out the rubber caps in the inside of the boot door and press the third brake light out (by pressing the two latches on each side of it), fill the edge with silicone and put back in place. I suppose replacing the bulb when it goes off will be tricky, but we'll see. I hope this helps.
Here are a couple of pictures of mine before I filled gap with silicone.
