The component (10) comprises a hollow body (12) having: an inlet (14, 14a, 14b), which is adapted to be connected to a source of pressurized liquid, for example the water supply network (WS); an outlet (16), adapted to deliver said liquid to a washing chamber (WC) defined by said washing tub (WT); a path (18) for the liquid, which is defined in the hollow body (12) between the inlet (14, 14a, 14b) and the outlet (16) and includes anti-return means (26, 26a) for said liquid under pressure; a passage (28), adapted to receive, at its inlet, vapor coming from the washing chamber (WC) and to discharge the vapor into the environment outside of the washing tub (WT); and a valve device (30) comprising a plug element (32), adapted to at least partially free and obstruct said passage (28).