2,3-Diamino-pyridinium 3-carb-oxy-4-hy-droxy-benzene-sulfonate monohydrate

In the title hydrated mol-ecular salt, C(5)H(8)N(3) (+)·C(7)H(5)O(6)S(-)·H(2)O, the ion pairs and water mol-ecules are connected by N-H⋯O, O-H⋯O and C-H⋯O hydrogen bonds, thereby forming a three-dimensional network. There is an intra-molecular O-H⋯O hydrogen bond in the 3-carb-oxy-4-hy-droxy-benzene-sulfonate anion, which generates an S(6) ring motif.