3. Rainwater-Harvesting Technology

Rainwater harvesting in buildings involves technology for its proper planning, design, installation, operation, and maintenance. Two major scopes of rainwater harvesting are (1) the use of rainwater for all general purposes and (2) recharging groundwater. In both cases, various functional techniques must be applied. The extent of technological involvement depends primarily on the introduction of various conditioning or treatment technologies in the harvesting system: sedimentation, filtration, and disinfection. Based on the application of these conditioning or treatment technologies, the rainwater-harvesting system in buildings may be classified as (1) a direct-use system, (2) a nonfiltered system, (3) a filtered system, and (4) a complete system. The development process of a rainwater-harvesting system in buildings has four aspects: (1) planning, (2) design, (3) construction, and (4) maintenance. In all aspects of rainwater harvesting‒system development, systematic approaches must be followed to ensure its sustainability. In this chapter, the major scopes of rainwater harvesting are introduced. The extent of technological involvement in the harvesting system is delineated. All aspects of rainwater-harvesting development in buildings and their systematical approaches are discussed. Finally, the problems and prospects of rainwater harvesting in buildings are identified.