Abstract: An insulated water storage tank preferably constructed from a rigid or hard plastic is disclosed which, in conjunction with associated piping and a series of valves, is directly connected to a dwelling's regular water supply line. The storage tank is filled with the regular the water supply line by opening an access or fill valve and closing a supply or intake valve. When the tank is filled the fill valve is also closed and waters travels normally through the supply line bypassing the storage tank. In the event of an interruption of the regular water supply, for whatever reason, a shut-off valve, which is normally opened, is closed preventing water flow from the main water supply and the supply valve is opened to allow the water stored in the tank to enter into the water supply line, thus providing an auxiliary supply of water.