A process separates out and removes water present in liquid fuels. The fuel supplies an internal combustion engine by a fuel delivery pump (12). Water is separated out at a filter (5) having a collecting space (27) for collecting separated water and connected upstream of the suction side (11) of the fuel delivery pump (12). The pump suction action counteracts outflow of water from the collecting space (27). Depending on the amount of water collected, the pump suction action is negated, and an outlet valve at an outflow orifice (37) of the collecting space (27) is opened by a discharge (43, 53) producing a pressure gradient enabling the discharge of water from the collecting space (27) over a discharge period when the fuel delivery pump (12) is operating.