Abstract: A pull-cord keeper provided for a window treatment assembly, where the keeper comprises a housing configured for secure mounting attachment on a wall near an upper portion of the window treatment assembly, the housing further defining a cavity therein; an opening in communication with the cavity; a spool adapted for rotational movement within the cavity to reel and collect through the opening a length of a slender, flexible material; and a sealed spring cartridge assembly for spring biasing the spool in a rotational direction for reeling the length of the slender, flexible material during a constant spring-loaded state.