In the title complex, [Zn(C12H6O4)(H2O)]n, a Zn-II polymer based on naphthalene-1,8-dicarboxylate (1,8-nap), the Zn-II atoms adopt an elongated octahedral coordination geometry. A zigzag chain is formed by mu(2)-aqua ligands and mu(2)-carboxylate groups of the 1,8-nap ligands. Adjacent parallel chains are further linked by 1,8-nap ligands, forming a twisted two-dimensional layer structure along the (100) plane.