Water scarcity is a real global threat that must be tackled to ensure biodiversity conservation, human welfare and development, and sustainability. Direct potable reuse (DPR) has been considered a promising strategy to guarantee public supply in regions with severe problems with water scarcity and high-water demand. The success of reuse practices mainly depends on the triad technology, regulation, and public acceptance. This study investigated public acceptance as a technical parameter to assess the implementation feasibility of DPR in large cities of developing countries. Residents of Campinas City (São Paulo, Brazil) were consulted through a multiple-response questionnaire addressing sociodemographic aspects, personal environmental perceptions, and the acceptable uses for wastewater reuse. The results showed a low rejection rate (∼7%) to DPR despite this not being regulated in Brazil. A total of 47% of the volunteers declared that they would accept the DPR of domestic sewage after appropriate treatments and technologies approved by the World Health Organization (WHO), and 46% would accept it after more information. Age was an essential factor for DPR acceptance, being greater among those between 30 and 45 years old. No statistically significant differences in potable reuse acceptability were observed among participants' sex and self-declaration of race. The majority of volunteers (85%) considered water reuse very important, and most participants (51%) already practice non-potable household water reuse daily and do so out of environmental awareness. Trust in the water supply concessionaire was a key factor in DPR acceptance. This study is essential for discussing innovative public-oriented solutions to achieve water security in developing countries, especially considering the scarcity of investigations on DPR acceptability in South America.