A water-processing domestic appliance with means (410; 620) for processing water and, upstream of said means, a cathode (35) and an anode (45) for the de-ionization of water in a de-ionization space (50) before said water is processed. A cathode screen (31) screens off a cathode region (30) from the de-ionization space (50), said cathode (35) being situated in the cathode region (30), while at least a portion of the cathode screen (31) is formed by a kation membrane (32). A much reduced maintenance necessity is achieved in that ions can be removed from the water to be processed without necessarily depositing on the cathode, and can be removed from the cathode region together with liquid.