A deionized-water cooling system for electrical equipment is provided. The system includes a cooling loop in which water comes into contact with the electrical equipment and a deionization bypass connected to the cooling loop. The deionization bypass includes a first filter component configured to remove dissolved oxygen, a second filter component configured to filter solid particles, a deionization cartridge configured to deionize water, and a plurality of valves configured to control a water flow within the deionization bypass.