Abstract: A filter having improved means of positive shutoff employs a rigid tubular fuel pervious core surrounded by flexible filter media that intercepts and resists the passage of particulate matter and water. A tubular retention sleeve is positioned within and in closed communication with the tubular core at one end thereof, the retention sleeve having an integral ball retention portion of reduced internal diameter. An end cap is secured to the other end of the tubular core member and has an annular sealing surface surrounding a flow passageway opening therethrough. A ball is normally positioned within the retention sleeve and in the engagement with the circumferential ball retention seat. When the flexible filter media has absorbed a sufficient quantity of water the pressure differential across the ball forces it to pass through the retention seat and to lodge against the sealing surface of the end cap, thereby closing further flow through the filter.