A water dispenser in a refrigerator door can include a filter casing in the door opening into the bottom of the dispenser housing. The filter casing can include a top wall positioned in the bottom of the dispenser housing, a head assembly at the bottom of the filter casing connected to the water supply and to a water outlet in the dispenser, and can include a filter casing drain. A filter cartridge in the filter casing can connect to the head assembly. The filter casing can include a filter retainer mounted adjacent the opening into the filter casing and can hold the filter cartridge connected to the head assembly in a first position and can release the filter cartridge in a second position. The filter casing can include a drain line leading from the filter casing drain to a pan outside the refrigerated space.