Cobrança de água de abastecimento como instrumento de Gestão Ambiental: o marco da micromedição na cidade histórica de Ouro Preto

Abstract

Control measures, reduction of consumption and financing of drinking water supply services in a municipality are essential strategies to ensure the safety and sustainability of service provision, as well as reducing the impacts of water scarcity. Several factors influence individual water consumption, and micro-measurement through the use of water meters, combined with a good tariff policy, can promote social justice and reduce waste, as observed in previous studies. In this context, the municipality of Ouro Preto, a location of great historical and cultural importance, in addition to recognized environmental wealth, has faced in recent years periods of low water availability, resulting from the disordered use of water over the centuries. And one of the reasons may be linked to the lack of measurement of individual consumption, absent until 2020, resulting in losses in distribution and per capita consumption estimated to be higher than the national average. Thus, the implementation of the Hydrometering Project by the service provider is considered a milestone in municipal sanitation management, a measure that aims to reduce water consumption and losses, preserving water resources. Therefore, by carrying out the research, the aim was to evaluate the effect of installing residential water meters on water consumption in the Supply System of the municipality of Ouro Preto, and the population's perception of the change in the way it is charged. Using data from the SNIS and provided by the municipality's water and sewage concessionaire, in addition to information from the literature, the scope of the first stage of the work was met. For the second phase, a questionnaire was applied to the population, approved by the institution's ethics committee, with questions related to consumption, evaluation of the service provided, willingness to pay (DAP, using the Contingent Valuation Method - MVC), as well as such as information on socioeconomic characteristics (age, gender, income, education, number of residents, type of residence). Based on the results obtained, it was found that with the implementation of micromeasurement (from 2021 to 2022), there was a significant reduction in per capita water consumption, per capita volume of sewage collected and revenue losses. The amount charged by the concessionaire increased in relation to the previously charged fixed rate. Regarding the population's perception of the change, despite more than 70% responding that they were unable to save water, there was a reduction in reported consumption before and after hydrometering. There was an influence of characteristics such as age, education and income on the acceptance of individualization of consumption and the willingness to pay for the water supply service, with emphasis on the older population who showed greater awareness. The DAP obtained was R$4.93/m3, higher than the average tariff charged by the concessionaire, although the tariff system currently charged, however, presents higher values than other companies for larger consumption ranges (especially above 15 m3) . Furthermore, it should be noted that the number of interviewees was reduced and the responses obtained may not reflect the perception of the Ouro Preto population. Characteristics of the municipality (number of districts, historic city and old pipes) could justify some of the observations made in the work (higher tariff prices and high losses), however a review can be carried out in consultation and participation of the population, aiming to raise awareness and reduce consumption.