Abstract: The water conservation system provides for the controlled circulation of heated water between an overhead water tank, which is mounted on the roof of a building, and an underground water tank for storing cooled water. The overhead tank has a feed outlet, a circulation outlet, and a circulation inlet formed therein. A first conduit is provided, with a lower end thereof being positioned within the underground tank. A pump draws water from within the underground tank, which is delivered to a second conduit. An upper end thereof is in fluid communication with the overhead tank. A third conduit is further provided, having an upper end in communication with the overhead tank and a lower end in communication with the underground tank. A programmable valve selectively controls water flow out of the overhead tank, which is delivered, via the third conduit, to the underground tank by gravity.