In the title compound, [RuCl(C(10)H(8)N(2))(C(6)H(12)S(3))]NO(3)·H(2)O or [RuCl(bpy)([9]aneS(3))]NO(3)·H(2)O, ([9]aneS(3) is 1,4,7-tri-thia-cyclo-nonane and bpy is 2,2'-bipyridine), the Ru(II) cation has a slightly distorted octa-hedral environment composed of three facially coordinated S atoms from ([9]aneS(3)), two N atoms from bpy and a chloride anion. The nitrate counter-ion and the water mol-ecule of crystallization are engaged in O-H⋯O hydrogen-bonding inter-actions, leading to a supra-molecular chain running parallel to the c axis.