Not sure where leak is coming from?  Side walls are wet on right side of back trunk and when I pull the latch up where spare and other bose parts sit, there is a puddle of water.  Can't figure out what from?  Any advice and input on how to fix would save me from taking to dealer and pay through nose.  Please and thank you for your feedback. 

i have and audi a4 2011...i, like others have a leak in the trunk/boot.never been able to sort it.i tried the usual get someone to sit in the trunk/boot while someone pours water over the back window.no result.here is a picture of the pool where the battery sits and look where one of the leads sits.had to take drastic action with mine and drill a hole in the boot.hope your more succesful than me lol.regards stephen

Could it be coming in from rear light seals, sunroof drain, rear wiper motor/washer system. 

Would it be worth sitting in the back of the car with rear seats down so you can observe where water is coming in if someone runs a hose/pressure washer over the car?