Abstract: A vortex valve (40) includes a housing defining a votex chamber(44), the housing having an inlet (46) through which liquid may enter the vortex chamber (44)in a manner to promote swirl within the vortex chamber (44) and an outlet (30) at one axial end of the vortex chamber (44). A wall of the housing is provided with an opening which is normally closed by a closure, this closure (6) being operable between the closed position and an open position in which livid may enter the vortex chamber (44) by-passing the inlet (46). The vortex valve is free from a spring device capable of urging the closure (6) from the open position to the close position. The vortex valve (40) may be provided at the outlet of a gully and is useful in enabling a blockage, which may occur at the inlet (46) of the vortex valve (40), to be by-passed, thereby draining any accumulated liquid in the gully. The blockage may then be removed when the gully is relatively dry.