In the title compound, (C3H7N6)2[Cu(C7H3NO5)2]6H2O, the coordination geometry of the CuII atom can be described as distorted octahedral. The equatorial plane is defined by four O atoms from two 4-hydroxypyridine-2,6-dicarboxylate ligands. The axial positions are occupied by the N atoms of the same ligands. There is an extensive three-dimensional hydrogenbond network reinforcing crystal cohesion.