Water quality comparison between a supply network and household reservoirs in one of the oldest cities in Brazil.

Water is an essential good for human life. This study aimed to verify the effects of household reservoirs on the physicochemical and microbiological characteristics of water in the municipality of São Mateus, Brazil, founded on 21 September 1544. Samples were collected in 83 residences, two samples per residence, one from the supply network and another from the household reservoir, making a total of 166 samples. The pH values, the free residual chlorine content and the turbidity values were determined. For the microbiological analysis, the defined substrate technology was used, allowing the simultaneous detection and identification of total coliforms and . The results showed that the samples from household reservoirs were more contaminated than those from the public supply network ( = 0.008). The high degree of microbiological contamination of the two groups may be directly associated to the reduced residual chlorine content in the samples, especially those from household reservoirs.