Graywater is defined as household wastewater generated by baths and showers, sinks, laundry, and kitchen/dishwashing. Reuse of graywater allows water to be used at least twice-initial use and local recycling. In some cases, water can be recovered for a third use-agriculture irrigation, thus leading to a savings of 10-20 percent of water consumption. This book examines the scientificprinciples of graywater, its reuse opportunities including practical examples and treatment designs, and the challenges of reuse. It also provides economic considerations regarding graywater reuse.Abstract:Graywater is defined as household wastewater generated by baths and showers, sinks, laundry, and kitchen/dishwashing. Reuse of graywater allows water to be used at least twice-initial use and local recycling. In some cases, water can be recovered for a third use-agriculture irrigation, thus leading to a savings of 10-20 percent of water consumption. This book examines the scientific principles of graywater, its reuse opportunities including practical examples and treatment designs, and the challenges of reuse. It also provides economic considerations regarding graywater reuse.