About 10 days ago, I noticed water on the driver's side dash and a damp spot in the corner of the headliner. Aha, I thought, the sunroof drain tube is leaking. Then I remembered that I had this problem a few years ago and fitted a new drain tube, secured with cable ties.
So, I took everything apart so as to drop the corner of the headliner to check if somehow the drain tube had come loose, the rubber had perished (unlikely), etc. All seemed okay so I poured a bottle of water down the drain tube to check for leaks. The water flowed out okay leaving a puddle on the garage floor. So, no blockage in the drain tube. I felt all around the drain tube but could not feel any water. Also, I didn't notice a damp spot on the headliner.

Any ideas where the water could be coming from.

 

try the hose test. spray an area, starting from low to high. check for leaks.

move a bit higher, repeat and check for leaks.

move a bit higher...

sounds like the drain but I guess it could be the windows?

 

+1 This is common in the older MINI when they get clogged or the rubber tube falls off.

https://www.northamericanmotoring.co...of-drains.html

 

I will definitely try it but when I poured a bottle of water down the drain it went thru to the floor, and I didn't see any on the inside of the headliner.