Filter system (10, 110) for a liquid medium to be filtered, in particular fuel or oil, comprising: - a filter housing (12, 112) having a housing pot (14, 114) and having a housing cover (16, 116) screwable onto the housing pot (14, 114) using a screwing movement or screwable into the housing pot (14, 114) in order to close the housing pot (14, 114), wherein the housing pot (14, 114) features a drain channel (32, 132) having a bottom-side drain opening (34, 134) for the liquid medium; - a filter element (18, 118) featuring on its lower end disc (36, 136) a closure member (38, 138) disposed eccentrically relative to the longitudinal axis (24, 124) of the filter element (18, 118), said closure member extending sealingly in a predetermined mounting position of the filter element (18, 118) in the filter housing (12, 112) via a bottom-side drain opening (34, 134) of the drain channel (32, 132) of the housing pot (14, 114) or extending sealingly into the bottom-side drain opening (34, 134) of the drain channel (32, 132) of the housing pot (14, 114), wherein the lower end disc (36, 136) of the filter element (18, 118) features a pipe connection (42, 142) extending away from the lower end disc (36, 136) in the axial direction and having a recess (44, 144), wherein the pipe connection (42, 142) is designed as a cylindrical section around the longitudinal axis (24, 124) of the filter element (18, 118) with an end face perpendicular to the longitudinal axis (24, 124), wherein the lower end disc (36, 136) of the filter element (18, 118) features the recess (44, 144) and the housing pot (14, 114) a positioning device (48, 148) corresponding to the recess (44, 144) and wherein the filter element (18, 118) is axially movable in the direction of the drain opening (34, 134) using the screwing movement of the housing cover (16, 116) and collectively rotatable with the housing cover (16, 116) around its longitudinal axis (24, 124) until the positioning device (48, 148) engages in the recess (44, 144) of the lower end disc (36, 136) and locks the filter element (18, 118) in a predetermined rotational position relative to the housing pot (14, 114), in which the closure member (38, 138) is axially aligned with the drain opening (34, 134), and wherein the filter element (18, 118) is movable in the axial direction into its predetermined mounting position in the filter housing (12, 112) using the screwing movement of the housing cover (16, 116), characterized in that the design of the recess (44, 144) and the positioning device (48, 148) correspond in such a way that an engagement of the threads on the housing cover (16, 116) and on the housing pot (14, 114) is only possible upon congruence of the recess with the positioning device (48, 148). - a filter housing (12, 112) having a housing pot (14, 114) and having a housing cover (16, 116) screwable onto the housing pot (14, 114) using a screwing movement or screwable into the housing pot (14, 114) in order to close the housing pot (14, 114), wherein the housing pot (14, 114) features a drain channel (32, 132) having a bottom-side drain opening (34, 134) for the liquid medium; - a filter element (18, 118) featuring on its lower end disc (36, 136) a closure member (38, 138) disposed eccentrically relative to the longitudinal axis (24, 124) of the filter element (18, 118), said closure member extending sealingly in a predetermined mounting position of the filter element (18, 118) in the filter housing (12, 112) via a bottom-side drain opening (34, 134) of the drain channel (32, 132) of the housing pot (14, 114) or extending sealingly into the bottom-side drain opening (34, 134) of the drain channel (32, 132) of the housing pot (14, 114), wherein the lower end disc (36, 136) of the filter element (18, 118) features a pipe connection (42, 142) extending away from the lower end disc (36, 136) in the axial direction and having a recess (44, 144), wherein the pipe connection (42, 142) is designed as a cylindrical section around the longitudinal axis (24, 124) of the filter element (18, 118) with an end face perpendicular to the longitudinal axis (24, 124), wherein the lower end disc (36, 136) of the filter element (18, 118) features the recess (44, 144) and the housing pot (14, 114) a positioning device (48, 148) corresponding to the recess (44, 144) and wherein the filter element (18, 118) is axially movable in the direction of the drain opening (34, 134) using the screwing movement of the housing cover (16, 116) and collectively rotatable with the housing cover (16, 116) around its longitudinal axis (24, 124) until the positioning device (48, 148) engages in the recess (44, 144) of the lower end disc (36, 136) and locks the filter element (18, 118) in a predetermined rotational position relative to the housing pot (14, 114), in which the closure member (38, 138) is axially aligned with the drain opening (34, 134), and wherein the filter element (18, 118) is movable in the axial direction into its predetermined mounting position in the filter housing (12, 112) using the screwing movement of the housing cover (16, 116), characterized in that the design of the recess (44, 144) and the positioning device (48, 148) correspond in such a way that an engagement of the threads on the housing cover (16, 116) and on the housing pot (14, 114) is only possible upon congruence of the recess with the positioning device (48, 148).