Affordability re-examined: beyond the health burden of safe water and clean cooking.

Clean fuels and safe water have a clear role in averting devastating health outcomes, yet unaffordability remains a major barrier to their uptake and to correct and continued use. Within the global health field, we have no consistent answer to the question of how we know that something is affordable and for whom. In this Viewpoint, we draw on the literature and our own fieldwork in Tanzania, Mexico, and India to show that commonly used metrics of affordability do not represent the true burdens of affording safe water and clean cooking in low-income and middle-income countries. We discuss the explicit and implicit assumptions in existing affordability metrics and call for augmented measures to shape affordability policies for water and cooking that advance global health goals. Research and policy must be realistic about who the user is, what the user's constraints are, and how these constraints shape any meaningful affordability metric. Unrealistic affordability metrics can only hide affordability crises and hinder progress on global public health goals.