A water purification apparatus is provided. The apparatus includes a casing and an electrode array. The casing has an outer surface, a substantially annular inner surface, and a water flow passage chamber surrounded by the substantially annular inner surface, the water flow passage chamber providing an outer annulus region and an inner central region. The electrode array features at least four electrodes in adjacent relationship to one another and circumferentially spaced apart from another about the outer annulus region, each electrode having a respective first planar surface and a respective second planar surface facing and substantially parallel to the respective second planar surface and the respective first planar surface of the adjacent electrodes on opposite sides thereof.