an inlet pipe configured to guide a flow of water;

an impeller housing fluidly connected to the inlet pipe to receive water introduced from the inlet pipe, having an impeller built therein, and including a first housing outlet and a second housing outlet formed parallel to a tangential direction of rotation of the impeller;

a flow path switch forming an internal space, including a first switch inlet and a second switch inlet, which fluidly communicate with the first housing outlet and the second housing outlet, respectively, and including a first switch outlet and a second switch outlet, which fluidly communicate with the first switch inlet and the second switch inlet, respectively;

a diaphragm that is formed as a single part, that is disposed in the internal space of the flow path switch, that separates the first switch inlet from the second switch inlet, and that separates the first switch outlet from the second switch outlet; and

a motor that is connected to the impeller and configured to rotate the impeller,

wherein the diaphragm is configured to selectively close (i) a first flow path through the first housing outlet, the first switch inlet, and the first switch outlet or (ii) a second flow path through the second housing outlet, the second switch inlet, and the second switch outlet,

wherein the diaphragm includes an elastic material and has a circular plate shape, the diaphragm including a curved central portion configured to protrude away from a plane of the circular plate shape with a curvature, and the diaphragm being pre-formed to maintain the protruding shape of the curved central portion and configured to close a side of the first flow path or the second flow path and open an opposite side of the first flow path or the second flow path,

wherein a protruding direction of the curved central portion of the diaphragm is configured to, based on an external force, change in an opposite direction relative to the plane of the circular plate shape, the protruding direction of the curved central portion of the diaphragm being maintained based on the external force being eliminated,

wherein the diaphragm defines a continuous curvature that varies from an outermost portion of the diaphragm to a middle of the curved central portion of the diaphragm based on protrusion of the curved central portion of the diaphragm, and

wherein the first flow path or the second flow path is configured to change between an open state and a closed state based on a change of the protruding direction of the curved central portion of the diaphragm.