The effect of the type of roofing and the seasons on the microbiological quality of rainwater

This paper presents the results of research on the bacteriological quality of rainwater collected directly from precipitation and various roof surfaces – concrete and ceramic roof tiles, galvanised sheet and a terrace covered with epoxy resin. Samples for the research were collected in a suburban area in 2015-2016. The quality of rainwater was assessed based on the results of bacteriological analyses (the presence of indicator bacteria and the total mesophilic and psychrophilic bacteria count). The effect of the seasons and the type of roofing on the microorganism count was discussed. Significant differences in the quality of rainwater collected from various roof surfaces, related to the roughness and chemical composition of the materials covering the roofs were indicated. In the rainwater examined, significant numbers of potentially pathogenic microorganisms such as Escherichia coli, coliforms and faecal streptococci were detected. The results obtained were the basis for indicating the possibility of using rainwater for various household purposes. Rainwater is not suitable for uses requiring the quality of water intended for consumption due to a great number of psychrophilic, mesophilic and faecal bacteria.