Propósito – Analysis of the judicial application of the fundamental right to water and its theoretical and practical implications in comparative law. Methodology/approach/design – Theoretical and jurisprudential analysis of the argumentative criteria used in cuts from different countries to implement the fundamental right to water. Results – Advantages and disadvantages of using the principle of reasonableness, minimum subsistence and proportionality as parameters for trials involving the constitutional right to water. Practical implications – The article shows that the principle of proportionality has comparative advantages when it comes to trials involving the fundamental right to water. Originality/relevance of the text – The article closes a gap in studies on the subject, especially in the face of problems arising from localised water crises or economic, social or legal disputes over water use in scenarios of resource scarcity.