Anomalous behavior of the hydrodynamic process in water extraction was observed in the two-phase system sodium bis(2-ethylhexyl) sulfosuccinate (AOT) water-in-oil (w/o) microemulsion (ME) phase and coexisting aqueous solution. The main factors causing the anomalous behavior were elucidated due to the experimental results and an analysis based on the following water extraction model : (1) rapid formation of equilibrium droplets at the liquid/liquid macro-interface due to the fast permeation of water through the bilayer that is formed between a ME droplet and the surfactant monolayer at the liquid/liquid macro-interface, (2) dependence of the diffusion coefficient of ME droplets on their size, and (3) change in the ME droplet size due to coalescence and redispersion of ME droplets. The increase in thickness of the diffusion boundary layer due to formation of heavier droplets at the macro-interface also played an important role for the extraction rates of water, especially for forward extraction of water at low agitation speed.