In the title compound, {[Cu(C(7)H(4)NO(4))(C(10)H(8)N(2))(H(2)O)]·H(2)O}(n), the Cu(I) ion is coordinated by the N atom from a 5-carb-oxy-pyridine-3-carboxyl-ate anion, two N atoms from two 4,4'-bipyridine (4,4'-bipy) ligands and one water mol-ecule in a distorted tetra-hedral geometry. The 4,4'-bipy ligands bridge the Cu(I) ions into polymeric chains propagating in [201]. The latticeand the coordinating water mol-ecules as well as the carboxy OH function are involved in the formation of inter-molecular O-H⋯O hydrogen bonds, which consolidate the crystal packing.