<p>A liquid level control valve including a cylinder member formed with a passage between an inlet and an outlet; a piston member slidable within the cylinder member, the piston and cylinder members being movable with respect to each other between a position in which the piston obturates the passage through the cylinder and a position in which the passage is open; a lever arm pivoted about an axis on one of the members and connectable to a float so that it is movable in response to the movement of the float on a body of liquid the level of which is to be controlled; and a linkage pivotally connected between the other member and the lever arm at a position on the lever arm spaced from the first mentioned pivot axis.</p>