The complete anion of the title hydrated molecular salt, 2C5H8N3
+·C8H4O4
−·2H2O, is generated by a crystallographic twofold axis. In the crystal, the cations, anions and water molecules are connected by N—H⋯O, O—H⋯O and C—H⋯O hydrogen bonds, forming a three-dimensional network. The crystal structure also features C—H⋯π interactions.