Development of a Water Quality Index (WQI) for public supply in the Vale do Rio Pardo region, RS, Brazil

Abstract This research developed a Water Quality Index (WQI) for public supply in the Vale do Rio Pardo Region, RS, Brazil (WQI-VRP), from the database of the 13th Regional Health Coordination, totaling 1175 samples. A filtration process resulted in 285 samples with the variables free residual chlorine, turbidity, apparent color, pH, fluoride, total coliforms and Escherichia coli. For water consumption purposes, the Water Quality Index developed by the Sanitation Company of Goiás, Brazil, was used. A multivariate calibration of the weights of importance of the parameters included in the original index was performed, resulting in the WQI-VRP. Comparing the medians of the two indexes, it was found that there were significant differences (p