Because of the large increase in the number of hotels in Brazil, added to the current concern to reduce the use of natural resources and the preference of some consumers for companies that adopt environmental measures in their management plans, rainwater-harvesting system become increasingly common in various levels of infrastructure in the country. The following paper does a bibliographic review of the current legislation that deals with the regulation of the use of the rainwater harvesting system, bringing international examples, beyond some pioneers Brazilian legislation, specifically aimed at the subject. The paper also brings a legislation proposal that encourages the management of rainwater on part of hotel projects as a way to enhance competitiveness, reduce costs, and contribute to a more rational and efficient use of water resources, reducing the volume of water that is discharged into the municipal drainage system.