Hello and help!!!

I got S reg Audi A 6 1.8 se auto which I love, but I got water gathering in the driver side footwell and rear passenger seat footwell (driverside) Any idea where it may be getting in. IM told it probably isnt as easy as a hole in the underneath of the car and also the water collects when I not even moved so guessing it must be dribbling down the centre column or maybe from windscreen area? Hoping this a common fault with an answer!!