A door entryway system is disclosed. The door entryway system may have a door sweep capable of attachment to a bottom of a door panel and a threshold assembly. The threshold assembly may include a threshold substrate, an upwardly open sill channel on the substrate and a substantially rigid threshold cap biased upwardly, and vertically adjustable by rotating during interaction with the door sweep. The threshold cap and door sweep contact to form a sealing barrier when the door panel is in a closed position. The threshold assembly may also include a cap base formed separate from the threshold cap, the cap base at least partially positioned within the sill channel, the cap base supporting the threshold cap.