In the title hydrate, C(19)H(25)N(3)O(3)S·H(2)O, the configuration at each chiral centre in the organic mol-ecule is S, with the hy-droxy and carbamate substituents being anti [O-C-C-N torsion angle = -179.3 (3)°]. The thio-pyrimidyl and carbamate residues lie to one side of the pseudo-mirror plane defined by the C(5)S backbone of the mol-ecule; this plane approximately bis-ects the benzene ring at the 1- and 4-C atoms. The dihedral angle formed between the terminal rings is 5.06 (18)°. In the crystal, supra-molecular tubes aligned along the b axis are found: these are sustained by a combination of O-H⋯O, O-H⋯N and N-H⋯O hydrogen bonds.