An in-duct humidifier has an evaporative pad onto the top of which water is dripped. Air passing through the pad evaporates the water to thereby increase the air's humidity. An improved tray for dripping the water onto the top of the pad has a sloped floor in which are a number of holes. A nozzle assembly which is mounted directly on the top of the tray and an improved arrangement of walls on the tray floor assists in delivering equal amounts of water to all of the holes, resulting in even distribution of water throughout the pad and more efficient operation of the humidifier.