The rainwater use in buildings provides a number of benefits, such as securing water supply, resilience to climate change, reducing runoff in cities and potable water savings. This article presents a literature review about the use of rainwater in Brazil. A state of the art theme was presented focusing on economic, environmental and social impacts. The legislation related to rainwater harvesting ‒ including the cities that have made such a practice mandatory ‒ was also assessed. The potential for water savings is directly related to the amount of precipitation, and inversely to the potable water demand. Despite the variation in the availability of water in the country and the differences between the design and the use of the projected systems, it was concluded that there is a high potential for potable water saving when using rainwater in buildings in Brazil. The systems are efficient to supply the rainwater demands, both quantitatively and qualitatively. Some new topics are suggested, such as the study of the benefits and impacts of the large-scale rainwater harvesting use, the study of new methodologies and the effects on the drainage systems. Finally, the need for financial investments in experimental research and innovative technologies was apparent, in order to improve rainwater management, depending on user needs and environmental impacts.