A multi-story water storage apparatus includes a plurality of stackable units arranged one above another along a vertical axis. Each of the stackable units includes a coupling portion arranged in alignment with the vertical axis, the coupling portion having a first space with a drainage hole. At least one of the stackable units is a storage unit having a storage portion arranged radially outwardly of the coupling portion with respect to the vertical axis. The storage portion is provided with a water storage compartment. The storage unit has an outlet passage through which water stored in the storage compartment flows into the first space
