Abstract: A method and system for removing impurities from water including heating a first gas stream including a first gas or a gas mixture and pre-humidifying the first gas stream using water from an impure water source. Heat may be transferred the first gas stream to a second gas stream, wherein the second gas stream includes a second gas or a gas mixture and wherein the first gas stream and the second gas stream flow in opposing directions. Water may be condensed out of the first gas stream and the second gas stream may be contacted with impure water, evaporating at least a portion of water from the impure water into the second gas stream to humidify the second gas stream. The first gas stream and the second gas stream are sustained at or near ambient pressure.