The reaction of manganese(II) nitrate with the proton-transfer compound piperazinediium pyridine-2,6-dicarboxylate, or (pipzH2)(pydc), in aqueous solution leads to the formation of the title compound, (C4H12N2)[Mn(C7H3NO4)2]6H2O. The anion is a six-coordinate complex with a distorted octahedral geometry around the central atom. In the crystal structure, intra- and intermolecular O—H O and N—H O hydrogen bonds connect the various components into a supramolecular structure.