In the title compound, C(18)H(24)N(4)O·H(2)O, the piperizine ring adopts a chair conformation and the dihedral angle between the phenyl and pyridine rings is 39.9 (3)°. The comformations of the attachment of the anisole and N-ethyl-pyridin-2-amine groups to the piperazine ring are +anti-periplanar. An intra-molecular C-H⋯O inter-action occurs. In the crystal, the water mol-ecule links the mol-ecules into chains through O-H⋯N hydrogen bonds. Weak N-H⋯O, C-H⋯N and C-H⋯O inter-actions further stabilize the crystal structure.