The asymmetric unit of the title compound, C4H14N2
2+·2C6H4NO2
−·H2O, consists of half of a doubly protonated tetramethylenediammonium dication, a pyridine-2-carboxylate anion and half of a solvent water molecule; the dication is located on a centre of inversion and a twofold rotation axis passes through the O atom of the water molecule. The carboxylate group of the anion appears to be delocalized on the basis of the C—O bond lengths. In the crystal structure, the components are linked by intermolecular N—H⋯O, N—H⋯N and O—H⋯O hydrogen bonds