Allied to the saturation of conventional supply systems and the pollution of the main water sources, the recurrent situations of droughts and shortages have been affecting the availability of water in many regions of the country, once abundant in water, such as the SE. The present study is part of the development of the necessary knowledge on alternative sources for meeting society's basic water demands. In this case, we focus on the reuse of wastewater to supply industrial demands in the metropolitan region of Rio de Janeiro (RMRJ), since this reuse can contribute to reducing the pressure on already saturated springs and supply systems, saving drinking water for more noble uses. This study aimed to evaluate, in terms of quantity, the potential to meet the demand for reuse water for industrial and non-potable purposes, based on the supply of treated effluent from four sewage treatment plants (STPs Alegria, Penha, Pavuna, and Sarapuí) in RMRJ, whose characteristics, such as location and installed treatment capacity, favor them as potential suppliers of regenerated water. As potential consumers, we considered industries in the transformation sector located within a radius of 10 km from these treatment systems (STPs). The great potential for reuse in the scenarios studied was verified by comparing the installed capacity of secondary treatment systems and the production of regenerated water available at the listed STPs in relation to the industrial water demands of a total of 728 processing companies located in the respective coverage radii defined from each STP. Many of these industries can be served by more than one treatment plant and, in addition, the large availability of potential reuse water supply in relation to demand also indicates the feasibility of meeting the water supply for other sectors and industrial typologies. The most representative sectors for the four STPs, from the point of view of the number of companies, were 22-Rubber/Plastics (rubber artifacts and plastic packaging), 25-Metal products (metal structures, machining), and 28-Machinery and equipment manufacturing. From the viewpoint of flow, the most representative were 20-Chemicals (especially petrochemicals/polymer products) for all the STPs and 30-Manufacture of other transport equipment, except motor vehicles, only for the Alegria and Penha STPs. Although the four ETE's listed present good potential for supplying reuse water, the Penha STP deserved more emphasis for presenting the highest required flow rate due to the number of companies that can be served in its surroundings, besides already having a reuse water production system in operation since 2007. Despite having a lower available flow rate, in addition to a greater distance in relation to the center of mass of the demands related to the industrial blocks, the Sarapuí STP can also be considered as a priority for being the closest to the largest potential consumption of reuse water identified by the study, i.e., the companies of the REDUC complex.