If you mix a organic soluable compound with EtOAc and water, mix well, and then let the phases separate, the majority of the organic compound should be in the EtOAc (lets say 90%) and the minority in the water, which will contain some of both EtOAc and some of the compound, (that would leave about 10% of the organic part). If you separate the layers and then rewash the water layer with EtOAc again, you will now get about the same percentages, about 90% in the organic layer and 10% in the aqueous layer. If yuo combine the organics, you should now have some EtOAc with about 99% of your organic material and a water layer with about 1% of the oroganic and a little EtOAc. One more time, and you can get ~99.9% recovery of the organic material back in the EtOAc, which will also contain some water. If you wash the EtOAc layer with brine, that will pull some water from the EtOAc layer, in theory, and then you can dry the EtOAc layer with some Na2SO4 or MgSO4 to remove the remaining water before evaporating the EtOAc. The numbers may vary, but for both solvents and compounds, there will be some solubility in water, but the more times you wash the water, the more organic you remove, and the effects of the mixed solvents will be mitigated.