Self-draining panel threshold assemblies including a reservoir chamber are discussed. The threshold assemblies comprise an interior sill portion, an exterior sill portion, and a drop-down chamber therebetween. The interior sill portion may include a condensation channel, which in one example, includes a roller track centrally positioned therein. The exterior sill portion includes a drain chamber and the reservoir chamber, where the reservoir chamber is positioned below and optionally to the exterior of the drain chamber. The drop-down chamber is partially defined by an elongate exposed weather-strip and an elongate covered weather-strip. In varying examples, a reservoir chamber height is equal to or greater than a water head height at a preselected wind load pressure. In certain examples, an effective threshold assembly height is less than or equal to ¾-inch, such as less than or equal to 1/2-inch. Methods and apparatuses related to the threshold assemblies are also discussed.