Criticalities in the microbiological monitoring of drinking water distribution systems: what could we do?

Recent progress in on-line microbiological measurement instruments has allowed real-time monitoring of drinking water distribution systems (DWDSs), uncovering microbiological dynamics and empowering the development of early-warning systems. While these instruments have become more common, several criticalities remain when conducting monitoring campaigns. For example, as most previous campaigns focus on single locations, microbiological dynamics and their variability within DWDSs are not well characterized, hampering the choice of effective sampling locations and timings. Furthermore, the identification of microbiological events, which could imply aesthetic, operational or sanitary issues, is confounded by the baseline dynamicity of bacterial concentration and communities in DWDSs. The goal of this work is, first, to highlight several criticalities which can affect DWDS microbiological monitoring campaigns and, secondly, to propose and evaluate possible improvement strategie