A water separator (108) includes a tube (112) defining a longitudinal axis, wherein the tube (112) includes a tube wall separating an interior (114) of the tube from an exterior (116) thereof. A tube insert (118) is mounted within the tube (112). The tube insert (118) includes a sheet (119) that is helically twisted about the longitudinal axis. An environmental control system (100) includes an air conditioner (102) with a discharge duct (104) for providing cooled air to an air conditioned space. A water separator (108) as described above is connected in line with the discharge duct (104) for passage of cooled air therethrough.