A cistern assembly for a flush toilet includes a cistern housing including a cistern lid and a cistern base, a cistern member pivotally attached within the cistern housing, and an actuator to pivot the cistern member relative to the cistern housing to discharge the stored water. The cistern member has a base wall that forms a chamber to store the water and a passageway to discharge the water from the chamber, the passageway has an internal inlet and a cistern outlet and is shaped to siphon water through the passageway. The actuator tilts the cistern member to actuate discharge of water through the passageway so that when the cistern member is pivoted and the passageway is moved below the water level of the stored water of the chamber, water is drawn through the passageway to the cistern outlet until air within the chamber enters the passageway preventing further water from being drawn into the passageway.