2-Thio-ureido-1H-benzimidazol-3-ium chloride monohydrate.

In the title compound, C8H9N4S(+)·Cl(-)·H2O, the cation is approximately planar, with a dihedral angle of 7.71 (8)° between the mean planes of the benzo-imidazole ring system and the thio-urea unit. In the crystal, cations, anions and water molecules of crystallization are linked by O-H⋯Cl, N-H⋯O, N-H⋯Cl and N-H⋯S hydrogen bonds into a three-dimensional network. π-π stacking is observed between the benzene and imidazole rings of neighbouring mol-ecules, the centroid-centroid distance being 3.5774 (11) Å.