A desalination system and method are based on the biological mechanism occurring in the mammalian kidney which utilizes colloid osmotic pressure and hydrostatic pressure to recover diluted salt solution from a concentrated one. The desalination system includes fluidly connected chamber compartments, one of which is filled with a charged substance, for example, a charged colloid polymer, to form a colloid salt solution when filled with the concentrated salt solution. Peripheral chamber compartments are filled with the concentrated salt solution. A system of semi-permeable membranes, not permeable to the charged substance, separate the chambers one from another. The system operates in the filling, equilibration, dilute, and collecting cycles which are controlled by opening and closing of the semi-permeable membranes. Desalination is based on the transfer of water due to osmotic pressure gradient across the membranes and is driven by hydrostatic pressure, thus providing energy efficient process. The charged substance is not consumed during the desalination and may be repeatedly used.