Having access to a safe water supply is important to improve a person's quality of life. We examine the relationship between the influence of water availability on monthly household expenditures (the dependent variable) and independent variables such as household characteristics, tank size, usage instructions and post-construction guidance, including the management of water-related health risks. The sample consisted of 301 respondents who harvest rainwater in Uganda. A multiple regression analysis was used to analyse the data. The findings show that post-construction guidance and tank size were significant variables. This study suggests the need for a follow-up to improve health after the installation of water supply equipment, i.e., to provide information about water risks, foster reading norms and facilitate the availability and affordability of information sources, e.g., subsidised newspapers and information support devices (computers). Additionally, this study shows the possibility of increased savings due to reduced expenditures on water from vendors and the management of water-related health risks caused by a water shortage, e.g., dehydration. Overall, the study reveals two possible ways to advance policy and health in developing countries: (1) ensuring sufficient post-construction guidance for all water resources; and (2) ensuring a sustainable supply of adequate safe water in households.