The title hydrate, C26H21NO·H2O, exhibits significant twists of the benzene ring [dihedral angle = 87.24 (6)°] and chalcone residue [C - C - C - C torsion angle = -94.46 (17)°] out of the plane through the quinoline ring system. The conformation about the C=C bond [1.341 (2) Å] is E. The solvent water mol-ecule forms hydrogen bonds to carbonyl O and quinoline N atoms derived from two mol-ecules and through the application of a centre of inversion, a 16-membered {⋯HOH⋯OC3N}2 synthon is formed to stabilize the resulting tetra-meric (two organic mol-ecules plus two water mol-ecules) aggregate. These are connected into a two-dimensional array via two C - H⋯O contacts, also involving the water mol-ecule. The layers stack along the c axis, being linked by C - H⋯π inter-actions.