A lithographic apparatus is disclosed including a liquid supply system configured to at least partly fill a space (10) between the projection system (PL) and the substrate (W) with a liquid (11), an outlet configured to remove a mixture of liquid and gas passing through a gap (28) between a liquid confinement structure (12) of the liquid supply system and the substrate, and an evacuation system (30) configured to draw the mixture through the outlet (14), the evacuation system having a separator tank (35) arranged to separate liquid from gas in the mixture and a separator tank pressure controller (40), connected to a non-liquid-filled region of the separator tank, configured to maintain a stable pressure within the non-liquid-filled region.