Restoring the historical role of chemistry to facilitate universal access to safe drinking water

Abstract Freshwater resources are partly polluted by chemicals, and treating them using certain chemicals can have negative impacts on their drinking quality. This communication presents a chemistry-free path to achieve universal access to safe drinking water, with a focus on rainwater harvesting (RWH). Acknowledging that rainfall is freshwater automatically changes the negative perception of rainwater in society. Based on this expected paradigm shift, the communication explores RWH as the sole sustainable solution to address water insecurity issues and achieve several United Nations Sustainable Development Goals (SDGs) within the remaining five years (to 2030). The viability of RWH in the Liesbeek River Catchment (Cape Town, South Africa) is reassessed as a case study. Carefully harvested rainwater is safe to drink in many locations, and in the event that, it is polluted, its treatment using frugal chemistry-free technologies is always possible. Rooftop RWH in the study area can supply the whole of Cape Town with safe drinking water year-round. The findings highlight the relevance of RWH, particularly rooftop RWH, in mitigating drinking water requirements everywhere, not only in water-scarce regions. The communication underscores the significance of well-designed RWH infrastructures for collecting, storing, eventually treating, and delivering rainwater for people’s needs.