Bis(2-carboxyanilinium) sulfate monohydrate

In the title hydrated molecular salt, 2C7H8NO2 +·SO4 2−·H2O, each cation in the asymmetric unit is stabilized by an intramolecular N—H⋯O hydrogen bond. The O atoms of the sulfate ion are disordered over two sets of sites with an occupancy ratio of 0.541 (13):0.459 (13), which possibly optimizes the acceptance of N—H⋯O hydrogen bonds from the cations. The crystal structure also features aromatic π–π stacking [centroid–centroid separation = 3.842 (2) Å] and a C—H⋯π interaction.