The asymmetric unit of the title compound, C(22)H(22)O(4)S·2H(2)O, contains one quarter of the organic mol-ecule and one half water mol-ecule, the site symmetries of the S atom and the water O atom being mm2 and m, respectively. The dihedral angle between the benzene rings is 76.27 (11)°. In the crystal structure, inter-molecular O-H⋯O hydrogen bonds link the mol-ecules into chains running parallel to the a axis.