Abstract: A liquid purification system, method and apparatus includes a plurality of operationally interconnected chambers. A supply or inlet chamber is held at about atmospheric temperature while other chambers of the system are held at a partial vacuum. The liquid to be purified is metered through a pressure differential between the supply or first chamber and a second chamber to induce spontaneous vaporization of the liquid. The temperatures of the chambers are reduced sufficiently so that, in the case of water, temperature-pressure conditions in the second chamber are below the triple point so as to condense ice and precipitate impurities into another chamber from the spontaneous vaporization. Condensation of the vapor in still another chamber recovers pure liquid. A temperature differential mechanism operatively connected to the chambers insures that condensation of the vapor will occur.