Hi I, am new to Audi forum. I recently purchased Audi A3 66 registration from private garage. I have found out few days ago that there is water leak in the boot rear passenger side, due to rain for couple of days now it getting worse. I am not sure where is this coming form. I am attaching pictures. Please anyone can help me. Thank you 

If you've bought this from the garage in the last 30 days then you are entitled for a full refund or for them to repair it. It could be the rear light seals or boot seal. 

Did this get solved? What was the issue? I have exactly the same problem and I'm lost in finding the leak

Hello Stijn, 

Thanks for joining. The original poster hasn’t been back to the forum since February, so it would probably be best to send him a PM.

You will probably find there are vent flaps near the bottom of the rear quarter panels and these could be the issue, but of course it depends how high up the water is starting. 
I don’t think there is much way around this other than to remove the inside trim panels to source the leak.

Perhaps you could come back to us with whatever you gather. 
Kind regards,

Gareth. 

On 11/19/2022 at 10:33 AM, Magnet said:

Hello Stijn, 

Thanks for joining. The original poster hasn’t been back to the forum since February, so it would probably be best to send him a PM.

You will probably find there are vent flaps near the bottom of the rear quarter panels and these could be the issue, but of course it depends how high up the water is starting. 
I don’t think there is much way around this other than to remove the inside trim panels to source the leak.

Perhaps you could come back to us with whatever you gather. 
Kind regards,

Gareth. 

I have the same problem with my A3.

I think its coming in the quarter light windows. I had the hose on mine and the inside of the rear quarter was wet. I'm in the process of sealing the rubbers. 

Graham