A valve assembly (I) for controlling the supply of water to a reservoir. The assembly (I) has a main body (2) having a floor (4) and side walls (3), an upper float (15) pivotably mounted within the main body (2) and a lower float (21) pivotably mounted beneath the main body (2). The floor (4) of the main body (2) having an aperture. The upper float (15) is upwardly movable to a position to shut off the water supply to the reservoir and the lower float (21) is movable upwardly to seal the aperture in the floor (4) of the main body (2) thereby to prevent water draining from the main body through said aperture or from prematurely filing.
