In the crystal structure of the title compound, C(6)H(13)N(3)S(2)·1.5H(2)O, weak N-H⋯S inter-actions between the zwitterionic mol-ecules are observed, leading to an extensively folded layered arrangement parallel to (100). There are three crystallographically independent water mol-ecules in the asymmetric unit, which are disordered and only half occupied.