Analysis of the rainwater harvesting system contribution toward the universalization of urban water access under the water utility perspective

Uma análise da contribuição de sistemas de aproveitamento de águas chuva para a universalização do acesso à água em ambientes urbanos: uma perspectiva da companhia de saneamento

ABSTRACT

The Brazilian New Legal Sanitation Framework approved in July 2020 included the Rainwater Harvesting Systems (RHS) as strategic alternative to reach universal urban water access in the country. Despite the vast literature on assessing the RWHS´s viability for households and establishments, there is lack of understanding on the impacts of the dissemination of this initiative to water utilities. This work proposed and applied a methodology to evaluate the impact of RHS dissemination on the performance of water utilities in the Federal District of Brazil. The methodology consisted of computing the potential water saving based on water balance of the RHS for non-potable water demand, selecting and evaluating operational and economic indicators of the water utility performance and computing economic evaluation of different scenarios of RHS dissemination. Results demonstrated that in most of the scenarios, the dissemination of RHS is not favorable to the water utility in terms of financial balance, mostly due to the loss of revenue given the reduction of water volume consumption. However, the financial balance has been extended to incorporate the possible sale of the saved water volume to categories of consumers with higher willingness to pay, such as, commercial, industrial or public users. Additional consideration of environmental benefits of RHS and other sale opportunities could also benefit the overall economic analysis of RHS as a public policy.

Keywords:
Decentralized sanitation; Urban water resources management; Economic evaluation