In the title hydrated mol-ecular salt, [Fe(C12H8N2)3](C9H5N4O)2·0.5H2O, the water mol-ecule site is half-occupied. The Fe-N bond lengths within the octa-hedral tris-chelate [Fe(phen)3](2+) ion (phen is 1,10-phenantroline) are indicative of a low-spin d(6) electronic configuration for the metal ion. The C-N, C-C and C-O bond lengths in the polynitrile anions indicate extensive electronic delocalization. In the crystal, the components are linked through O-H⋯N hydrogen bonds, forming [100] chains, as well as through Coulombic inter-actions.