A pressure support device includes a humidification system (10) to control the humidity of a pressurized flow of breathable gas generated by the pressure support device. The humidification system includes a liquid storage chamber (32) and a humidification chamber (34). When in an operational orientation liquid travels from the liquid storage chamber to the humidification chamber through a serpentine feed path (38) due to gravity. The serpentine shape of feed path halts the flow of liquid responsive to the device being tilted out of an operational orientation.