See also:

Observe the following when refueling
The fuel tank is full when the filler nozzle clicks off the first time. Handling fuels Obey safety regulations posted at the gas station. ...

Condensation under the parked vehicle
When using the automatic climate control, condensation water develops that exits underneath the vehicle. Therefore, traces of condensed water under the vehicle are normal. ...

Fuel tank capacity
Approx. 22.5 US gallons/85 liters, including the reserve capacity of approx. 2.1 US gallons/8 liters. X5 xDrive50i/X6 xDrive50i: reserve capacity of approx. 3.2 gallons/12 liters. Refuel promp ...