A storage-type water heater comprising: first heating means for heating water to generate first hot water; a hot water storage tank configured to store the first hot water generated by the first heating means; a heat exchanger configured to preheat municipal water through heat exchange between the first hot water taken from the hot water storage tank and the municipal water; second heating means for heating the municipal water preheated by the heat exchanger to generate second hot water; and control means for supplying the first hot water taken from the hot water storage tank or the second hot water generated by the second heating means, wherein the hot water storage tank and the second heating means are connected in parallel to (i) a feedwater terminal from which the municipal water is supplied and (ii) a hot-water supply terminal to which the first hot water and the second hot water are supplied, a pressure reducing valve is disposed between the feedwater terminal and an incoming water path to the hot water storage tank, and an incoming water path to the second heating means is branched between the feedwater terminal and the pressure reducing valve, a primary side path through which the first hot water taken from an upper portion of the hot water storage tank flows and a secondary side path through which the municipal water flows are disposed in the heat exchanger, characterized in that the storage-type water heater comprises a suction switching valve configured to switch between the primary side path and a path through which water taken from a lower portion of the hot water storage tank flows, the suction switching valve being disposed in a suction path to a pump, and a discharge switching valve configured to switch between an incoming water path to the first heating means and a path through which water flows into a lower portion of the hot water storage tank, the discharge switching valve being disposed in a discharge path from the pump. first heating means for heating water to generate first hot water; a hot water storage tank configured to store the first hot water generated by the first heating means; a heat exchanger configured to preheat municipal water through heat exchange between the first hot water taken from the hot water storage tank and the municipal water; second heating means for heating the municipal water preheated by the heat exchanger to generate second hot water; and control means for supplying the first hot water taken from the hot water storage tank or the second hot water generated by the second heating means, wherein the hot water storage tank and the second heating means are connected in parallel to (i) a feedwater terminal from which the municipal water is supplied and (ii) a hot-water supply terminal to which the first hot water and the second hot water are supplied, a pressure reducing valve is disposed between the feedwater terminal and an incoming water path to the hot water storage tank, and an incoming water path to the second heating means is branched between the feedwater terminal and the pressure reducing valve, a primary side path through which the first hot water taken from an upper portion of the hot water storage tank flows and a secondary side path through which the municipal water flows are disposed in the heat exchanger, characterized in that the storage-type water heater comprises a suction switching valve configured to switch between the primary side path and a path through which water taken from a lower portion of the hot water storage tank flows, the suction switching valve being disposed in a suction path to a pump, and a discharge switching valve configured to switch between an incoming water path to the first heating means and a path through which water flows into a lower portion of the hot water storage tank, the discharge switching valve being disposed in a discharge path from the pump.