This project aims at observing existing WaSH interventions to determine the relationships between water quality and short-term variability in weather conditions and the relative ability of these WaSH interventions to protect human health against climate change impacts in Tanzania. The proposed longitudinal cohort observational study will be conducted across three sites from different climatic regions in Tanzania; coastal Dar es Salaam, South East wet Kilombero District, Morogoro Region and northern dry Kondoa District, Dodoma Region.