Motor vehicle with a water box

The vehicle (4) has a left fresh air intake opening (12) that is adapted to flow the fresh air from outside to an interior (11) of an inner wall of a water tank (1) and to discharge through an air outlet opening (15). A water outlet (16) is adapted to release water from the interior. A pressure-lossy structure (17) defining a pressure loss between the inlet and outlet openings is arranged in the interior. A right fresh air inlet opening (13) which is adapted to flow the fresh air to the interior, is located downstream of the pressure-lossy structures. An independent claim is included for a method for controlling an air pressure and/or an amount of air to an air outlet opening of a water tank of a motor vehicle.