A fabric treatment appliance comprises a steam generator (60) having a chamber configured to hold water, a supply conduit configured to transport water to the steam generator chamber, a weight sensor (120) outputting a signal responsive to the weight of the steam generator, and a controller (64) coupled to the weight sensor and configured to control a flow of water through the supply conduit based on the signal from the weight sensor. The disclosure provides methods of water supply control that can employ the weight sensor.