Self-diffusion measurement sby Pulsed Field Gradient Spin Echo methods (PFGNMR) have been used to characterize the water poor region of the system water-Triton TX/100. The measurements thus obtained wre verified with electrical conductivity and density. Experimental evidence suggests that the reverse solution phase, L 2, can be divided in two regions, the molecular solution and the reverse micellar. Estimates of hydration numbers and of the aggregate size and shape were obtained from experiments. At low water content, H 2O is almost completely bound to the polyoxyethylene chains of Triton, but at concentrations higher than 13 water wt%, it is freely diffusing in a three dimensional network.