The irrigation system provides for the purification of water from a source of impure water, and for the distribution of the purified water to crops for agricultural irrigation purposes. The system includes a specially configured tank, the tank being partially evacuated to lower the pressure therein to vaporize or boil the water in the tank under vacuum. Heat energy may be provided to the tank by solar reflectors or other heat source. The purified water vapor passes from the tank and through a heat exchanger. The cooled vapor flows through a distribution network and out through a plurality of specially configured moisture distribution heads to flow into the soil. The distribution heads may also distribute liquid fertilizer to the soil.