Water is the most important resource in the world. The importance of a safe water supply and effective sanitation systems are paramount to maintaining public health standards in both developed and developing countries. With increasing population pressures and industrial and agricultural development, the prevention of water pollution and the management of water resources are increasingly important everywhere. Large-scale centralised supply, distribution and treatment systems (including dams, reservoirs, pipe networks and treatment plants) have evolved to satisfy increasing water demand in many parts of the world. However, many of these centralised systems are struggling to meet water demand from an ever increasing population in an unpredictable climate.