Abstract: A multi-level film fill industrial size water cooling tower is disclosed having upper and lower film fill packs arranged one above the other, and wherein a self-balancing hot water distribution system is provided for directing flows of hot water from the main supply line to respective distributors which are proportional to flow of hot water in the main supply line. Laterally extending distribution pipes connected to the main supply line in overlying relationship to the film fill packs have restrictor nozzles thereon all located in a common horizontal plane, so that the flow of hot water from all of the nozzles remains proportional to the flow in the main supply line. Each of the restrictor nozzles is vented to the surrounding atmosphere to prevent creation of significant negative pressure on the hot water flowing from each nozzle.