In the title compound, (C(12)H(11)N(3))[BiCl(5)]·H(2)O, the Bi(III) atom is coordinated by five chloride anions in a distorted square-pyramidal geometry. The planar imidazole ring system [maximum deviation = 0.012 (3) Å] is oriented at a dihedral angle of 6.08 (5)° with respect to the protonated pyridine ring. An O-H⋯Cl inter-action links the water mol-ecule to the dianion. In the crystal structure, inter-molecular O-H⋯Cl, N-H⋯O and N-H⋯Cl inter-actions link the mol-ecules into a three-dimensional network.