Some water drain valves tend to fill with water which may freeze, thereby jamming the valve. This invention provides an aircraft water drain valve comprising a passageway, a shaft, a first sealing member and a second sealing member. The shaft is moveable between an open position in which the first and second sealing members are arranged to allow free passage of fluid through the passageway, and a closed position in which both the first and second sealing members are arranged to prevent free passage of fluid through the passageway thereby preventing ingress of fluid into the region between the first and second sealing members. Thus water may be hindered from collecting and freezing in the part of the valve close to the cold wall of the fuel tank.