To provide a tank device capable of supplying clean water within reach and surely in case of an emergency.

A horizontal feed pipe with specific length is connected to the outside of the bottom of an oval water storage tank 1 set to a water running faucet J and a space within reach through leg frames 2, an underground water service pipe 6 having a valve 4 on the upper stream side and a chuck valve 5 on the lower stream side and a water storage faucet 7 are connected to a middle site of the horizontal feed pipe, and a valve 8 is mounted to the outside end. While, a drain outlet pipe 9 mounting a chuck valve 10 on the upper end is connected to the top of the oval water storage tank 1, the middle site and water running faucet J are connected to each other with a water pipe 9a, the chuck valves 5 and 11 are operated to prevent the overflow of reservoir water in the water storage tank 1 when water is cut off in emergencies, and the chuck valve 10 is naturally opened in atmospheric pressure to smoothly execute the intake of reservoir water in the water storage tank 1 by opening the water storage faucet 7.