The title compound, {[Zn₂(SO₃)₂(C₁₀H₈N₂)]·H₂O}_n, is a two-dimensional polymer built up of a [ZnSO₃]_n chain evolving around a 2₁ axis and interconnected by a 4,4′-bipyridine spacer. The resulting two-dimensional structures are linked, in turn, by hydrogen bonding mediated by the solvent water molecule. The organic ligand lies on a centre of symmetry located on the mid-point of the bond between the rings, while the solvent water molecule is halved by a twofold axis passing through the O atom.