This study examines whether water scarcity context affects water conservation decision behaviour. We do this analysing a decision model that includes perceived message credibility, water consumption risk, and personal involvement variables. The sample consists of residents of more than 20 Spanish cities, and contexts of water scarcity (n = 420) and non-scarcity (n = 217) are compared. Spain was chosen because it is one of the most water-stressed (difference between consumption and reserves) countries in Europe, and water scarcity is a key factor affecting water conservation efforts. We employ regression analysis with partial least squares (PLS) and multi-group techniques. Two relevant findings can be highlighted. First, the most relevant variable in the model is personal involvement in water conservation practices. Second, although in general our model is not sensitive to the water scarcity context, we observe that individuals living in areas with water scarcity report greater levels of personal involvement and water conservation decision behaviour. We conclude by providing the implications for water managers and policymakers and suggesting avenues for future research.