To automatically drain water downstream of a guide pipe when a shut-off valve closing/opening a water supply pipe is closed.

This is a water supply facility equipped with a shut-off valve opening/closing a water supply pipe 2 and a guide pipe 6 supplying water from the tip to the outside by water application from the water supply pipe when the shut-off valve is continuously in open state from the shut-off valve to the downstream side. In this case, a drain valve 7 is provided at the guide pipe 6, and the drain valve comprises an air hole 10 for introducing atmosphere to the guide pipe and a valve body 13 which closes air hole by the water pressure in the guide pipe.