The crystal structure of the title compound, [Sn(CH3)(3)(C17H11ClNO2S)(H2O)], contains hydrogen-bonded infinite planes, wherein each trimethyltin moiety is coordinated to a water molecule and an O atom of the carboxylate ligand. The Sn atom has a distorted trigonal-bipyramidal geometry with three methyl groups in the equatorial plane [mean Sn-C 2.114(7) Angstrom]. The O atoms bonded to the Sn atom in the axial positions have significantly different Sn-O bond lengths [2.167(4) and 2.490 (4) Angstrom].