Hydromagnetic Toilet Valve, constituted by a body, a magnet cluster, an assembly consisting of shaft with a closing gasket and a floater to open and close the valve; it uses three forces: magnetic, exerted by the floater with the tank's water level and the force of the exterior line pressure; we achieve a closure that does not permit water in or out, when the closing is done, it immediately turns into an anti-syphoon valve because it does not allow the liquid in the deposit to be dragged out by gravity in absence of water on the line. Upon finding vacuum the deposit indicates that water was used for a normal bowl discharge or because the liquid leaked by the drain pipe because of anomalies in the discharge system, this valve will supply only what's necessary to fill the toilet bowl and tank to do a required flush, this valve won't supply water if the knob is not actuated to open the valve, or the lever to perform the same function.