Flood prevention systems for appliances

A system for preventing and controlling flooding caused by blockages in the drain line or caused by damage to a water supply line or a water drain line of a washing machine, dishwasher and the like, including (i) a motorized cold water supply line valve, (ii) a motorized hot water supply line valve; (iii) a sealed connection adapted for connection to the appliance discharge line, connection to an atmospheric vent, connection to a float switch and connection to a sewer line; (iv) a including a liquid sensor adapted to generate a fault signal upon detecting liquid on a surface near the washing machine and to transmit the leakage signal to a control processor; and (v) the control processor operable to shut off power to the washing machine upon receipt of the fault signal, and to close the water supply line valves upon loss of power to the washing machine.