Health Burden of the Consumption of Rooftop Rainwater Harvesting Systems in Buea Sub–Division, Cameroon

Roof harvested rainwater is generally considered to be safe and is mostly used without prior treatment. However, the population is exposed to several health risks associated with contaminating pathogens found in harvested rainwater. This study assessed the health risks of the currently practiced rooftop rainwater harvesting partially used for drinking water supply. Multi-stage sampling was employed to evaluate the microbial properties of 20 rainwater cistern across four communities (Bonakanda, Bova I and II, and Ewonda) in Buea Sub-division. A total of 358 households were randomly sampled for rainwater harvesting potentials and a semi-quantitative risk assessment matrix was used to estimate potential health risks of untreated harvested roof rainwater for drinking purpose. Rainwater is a principal cost-effective alternative to other sources of water supply for households. While its uses for other purposes such as cleaning and irrigation present limited risks to the population, its sparing use for drinking without any treatment was observed to results in health risks involving sporadic illnesses linked to bacterial diarrheas due to Salmonella and Campylobacter, bacterial pneumonia due to Legionella, botulism due to Clostridium, tissue helminths and protozoal diarrheas from Giardia and Cryptosporidium. The study thus recommends pre-treatment of harvested rainwater through filtration, chlorination, ultraviolet disinfection, and or boiling, for potable purposes.