The treatment and supply of drinking water is a challenging task that includes many diverse aspects ranging from water quality management in catchments, operation and control of water treatment plants, distribution of treated water, community participation, project management, etc. The purpose of this handbook is to provide comprehensive information specifically on all aspects related to the treatment of water for domestic use. The focus is on the operational aspects of treatment plants and processes and not on process design. Sufficient background and process descriptions are provided to enable a proper understanding of the functioning of the different processes and on aspects such as the suitability of processes for different types of water and the limitations of different processes.