A global review of the microbiological quality and potential health risks associated with roof-harvested rainwater tanks
CITATION: Hamilton, K., et al. 2019. A global review of the microbiological quality and potential health risks associated with roof-harvested rainwater tanks. npj Clean Water, 2:7, doi:10.1038/s41545-019-0030-5.
The original publication is available at https://www.nature.com
A broad body of literature has been published regarding roof-harvested rainwater quality around the world. In particular, the presence of fecal indicator bacteria and pathogenic microorganisms has raised concerns regarding the acceptability of rainwater for potable and non-potable uses. As the use of molecular assays has improved understanding of the diverse microbial communities present in rainwater tanks and their role in providing benefits or harm to human health, a comprehensive review is needed to summarize the state of the science in this area. To provide a summary of microbial contaminants in rainwater tanks and contextual factors, a comprehensive review was conducted here to elucidate the uses of rainwater, factors affecting water quality, concentrations of fecal indicators and pathogens, the attribution of pathogens to host sources using microbial source tracking, microbial ecology, human health risks determined using epidemiological approaches and quantitative microbial risk assessment, and treatment approaches for mitigating risks. Research gaps were identified for pathogen concentration data, microbial source tracking approaches for identifying the sources of microbial contamination, limitations to current approaches for assessing viability, treatment, and maintenance practices. Frameworks should be developed to assess and prioritize these factors in order to optimize public health promotion for roof-harvested rainwater.