The title salt, C3H6N3S2 (+)·Cl(-)·H2O, crystallized with two organic cations, two chloride anions and two water mol-ecules in the asymmetric unit. The methyl C atoms deviate from their respective bound ring planes by 0.081 and 0.002 Å. In the crystal, the components are connected via N-H⋯O, N-H⋯Cl and O-H⋯Cl hydrogen bonds, forming sheets lying parallel to (100). The sheets are linked into bilayers by O-H⋯Cl hydrogen bonds involving the chloride ions and water mol-ecules. Within the bilayers there are π-π inter-actions [inter-centroid distances = 3.4654 (4) and 3.4789 (4) Å] involving inversion-related cations.