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 . <EOS>