This book provides a detailed description of a Water Purifier System, how it works, its function, component parts and materials used, and the design process. After its construction, sample of non-potable water from an untreated well was purified by the system. The effluent water (outlet from the system) of this sample was then tested to determine its properties. The property values of the test results closely matched standard values of Nigerian Industrial Standard (N.I.S), Environmental Protection Agency (EPA), and the World Health Organization (W.H.O). This proved that this Household Water Purifier System is efficient, reliable, easy to construct,has a reasonable cost, and can be used to provide potable water in communities with water pollution challenges.