The permeation characteristics of a series of chlorinated hydrocarbons, which have different carbon and chlorine numbers, have been investigated through a poly(dimethylsiloxane) (PDMS) membrane in the pervaporation of pure hydrocarbon organics and dilute organic aqueous mixtures, respectively. The pervaporation of the dilute organic aqueous mixtures was performed at different feed compositions and feed temperatures. In particular, this study focused on examining the effects of both the chlorine and carbon numbers in the respective organic moieties on the permeation performance with respect to permeability, diffusivity, and solubility coefficients. The permeation behavior of the organic aqueous mixtures was analyzed in terms of their dependence on both the feed temperature and composition, and was compared with the permeations of the respective pure organic liquids. The permeation behavior of the chlorinated hydrocarbon aqueous solutions were interpreted in terms of the effects of the interaction between the organic permeant and the membrane material, and the interaction between the water and organic molecules absorbed in the membrane, resulting in a corresponding plasticization action on the membrane material. It was confirmed that the permeation of an organic permeant through the rubbery membrane is dominated by the sorption process rather than by a diffusion process.