Bis(2-carboxy-anilinium) sulfate monohydrate.

In the title hydrated mol-ecular salt, 2C(7)H(8)NO(2) (+)·SO(4) (2-)·H(2)O, each cation in the asymmetric unit is stabilized by an intra-molecular 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 inter-action.