Abstract: A vacuum cleaner dirt containment system with a bag chamber having an open end, an outlet adapted to be in fluid communication with a vacuum fan inlet located on the vacuum cleaner housing, and a plurality of locator ribs extending from an inner wall of the bag chamber. Each locator rib has a landing adjacent an inner wall of the bag chamber, and a pin located inward of the landing and extending from the landing towards the open end of the bag chamber. A filter bag assembly is adapted to be inserted into the bag chamber, and has a flange attached to an open end of a permeable filter bag. A flange air inlet passes through the flange into the bag. The flange has openings located to be inserted over the locator rib pins, and support segments located to abut the locator rib landings. The lid is selectively attachable to the open end of the bag chamber, and includes an air inlet mounting tube that extends into the flange air inlet when the lid is attached to the open end of the bag chamber.