| abstract |
(57) [Summary] [PROBLEMS] To provide a rainwater storage device capable of maintaining or improving the quality of stored water in a water storage tank for storing rainwater. SOLUTION: A water storage tank 1 has a water storage circulation device 4 and a water storage tank 1. Circulating device 4 for circulating and flowing stored water W2 therein, useful bacterial propagation means 10 for facilitating propagation of useful bacteria for decomposing organic substances and the like in stored water W2, aeration means 1 1 and the like are disposed, and the stored water W2 is used as high quality intermediate water by maintaining or improving the quality of rainwater filled as the stored water W2 in the water storage tank 1. Further, in this case, at least a part of the necessary electric power can be covered by electric power from a natural power generation unit that performs solar power generation, wind power generation, and the like. |