4-[2-(4-Meth-oxy-phen-yl)eth-yl]-3-(thio-phen-2-ylmeth-yl)-1H-1,2,4-triazol-5(4H)-one monohydrate.

In the title compound, C(16)H(17)N(3)O(2)S·H(2)O, the triazole ring makes a dihedral angle of 34.63†(6)° with the benzene ring. The thio-phene ring is disordered over two orientations [occupancy ratio = 0.634†(4):0.366†(4)] which make dihedral angles of 54.61†(16) and 54.57†(31)° with the triazole ring. Inter-molecular N-H⋯O and O-H⋯O hydrogen bonds stabilize the crystal structure.