This paper presents a general approach to rainwater as a water resource. The use of rainwater, a common practice in many civilizations of the past throughout the planet, is regaining prominence in both developed and developing countries. In the latter and especially in some rural areas of Asia, Africa and Latin America, rainwater may provide more abundant and better-quality water than distant and polluted surface or groundwater sources. In developed countries, the use of rainwater diminishes pressures on public networks, satisfying certain uses without having to resort to very expensive and environmentally problematic infrastructures. However, rainwater suffers from a major problem which is the uncertainty of supply, especially in the absence of wellsized catchment surfaces and storage tanks for areas of scarce and erratic rainfall. In hydrosocial terms, the use of rainwater can empower communities in many parts of the planet fostering decentralized governance and control of water resources.