The title compound, [K(C6H4N5)(H2O)2]n, was synthesized by hydrothermal reaction of KOH with 4-(5-tetrazolio)pyridine. The K atom has a distorted octahedral coordination environment and is coordinated by two axial N atoms from the organic ligand and by four water molecules in the equatorial plane. The molecules as a whole are located on crystallographic mirror planes; the K atom is also located on an inversion center. Both the water molecules and the organic ligands act as bridges to link symmetrically the adjacent K atoms into polymeric chains parallel to the c axis. O—H⋯N hydrogen bonds involving the water O atoms and aromatic π–π interactions [centroid–centroid distance 3.80 (2) Å] between the pyridine and tetrazole rings build up an infinite three-dimensional network
