A thermal power plant for recovering water from exhaust gas includes a gas turbine, a heat recovery steam generator for generating steam by supplying exhaust combustion gas exhausted from the gas turbine as heat source, a water recovery system installed on the downstream side of the heat recovery steam generator, a recovered water system for supplying a part of the water recovered by the water recovery system, allowing the water to be circulating as circulating water, a feed water system for supplying the heat recovery steam generator with other part of the water recovered by the water recovery system as feed water, pH adjusting systems, and a control system for controlling the volumes of pH adjusters supplied from the first and second pH adjusting systems.