Climate-Sensitive Microbial Water Quality and Household Water Security in Saharan and Sahelian Africa

Climate change is intensifying challenges to microbial water quality and household water security across Saharan and Sahelian Africa, where water scarcity, variable infrastructure, and reliance on decentralized and informal water sources can increase vulnerability to contamination. This structured narrative review synthesizes evidence on how climatic stressors, including extreme heat, ultraviolet radiation, drought, flooding, rainfall variability, and dust events, influence microbial contamination, persistence, transport, and exposure across groundwater, surface waters, drinking-water distribution systems, and household storage. Heavy rainfall and flooding can mobilize fecal contamination and microbial hazards into water sources, whereas drought and water scarcity can increase dependence on marginal supplies, prolong household storage, and create conditions favorable to post-collection contamination and microbial regrowth. Climatic effects vary across microbial groups and water matrices: temperature, sunlight, turbidity, sediments, biofilms, and hydrological conditions can differentially influence bacterial, viral, and protozoan persistence and transport. Saharan dust also represents a potential pathway for long-range microbial dispersal and deposition, although direct evidence linking individual dust events to pathogen concentrations in drinking-water sources remains limited. The review further shows that microbial water quality is insufficiently integrated with broader dimensions of household water security, including availability, reliability, accessibility, and perceived safety. Strengthening the evidence base will require greater integration of microbial, climatic, hydrological, infrastructure, and household water-security data to support climate-resilient water management and public-health protection in Saharan and Sahelian communities.