The title compound, C₁₀H₈N₂O₂·H₂O, consists of an N-hydroxyquinoline-2-carboxamide molecule in the keto tautomeric form and a water molecule connected through an O—H...O hydrogen bond. The N-hydroxyquinoline-2-carboxamide molecule has a nearly planar structure [maximum deviation = 0.062 (1) Å] and only the hydroxy H atom deviates significantly from the molecule plane. In the crystal, π–π stacking between the aromatic rings [intercentroid distance = 3.887 (1) Å] and intermolecular O—H...O hydrogen bonds organize the crystal components into columns extending along the b-axis direction.