Water tank and water heater with water tank

The invention discloses a water tank and a water heater with the water tank. The water tank is an open water tank. The forming position of a user water returning opening of the water tank is higher than the forming position of a user water taking opening and higher than the half position of the water tank, and the forming position of the user water taking opening is higher than the forming position of a hot water inlet and the forming position of a circulation water outlet. The water tank further comprises a water level inducting device arranged in the water tank and a water replenishing control device, wherein the water replenishing control device is in communication connection with the water level inducting device and is used for controlling a user water supply pipe to be opened or closed. In this way, according to the water tank, the interior of the water tank is always in the high water level state by controlling the water level, convection heat exchanging between water in the upper portion of the water tank and water in the lower portion of the water tank can be reduced, more obvious cold and hot water layering can be formed accordingly, and the amount of produced hot water and the water using comfort degree are increased; and meanwhile the maintaining cost of the water tank is reduced, and the aims of saving energy and reducing the use cost are achieved. The invention further provides the water heater with the water tank.