The utility model relates to a non-pressure enamel solar water heater water tank. The water tank comprises a water tank body, and a heating coil is arranged in the water tank body. The water tank further comprises a water inlet pipe and a water outlet pipe. The water outlet pipe is a sleeve which comprises a first-segment pipe and a second-segment pipe. The first-segment pipe is fixedly connected with the water tank body to form a whole of which the lower end is exposed out of the outer side of the water tank. The lower end of the first-segment pipe is connected with a close nipple. The inner diameter of the first-segment pipe is equal to the outer diameter of the second-segment pipe. The second-segment pipe is embedded in the first-segment pipe. A limiting protrusion is arranged at the top end of the first-segment pipe. An enamel floating ball is arranged on the top of the second-segment pipe. The non-pressure enamel solar water heater water tank has the advantage that the sleeve structure is adopted for the water outlet pipe, the enamel floating ball is arranged at the top end of the water outlet pipe and can float in the vertical direction along with the change of the water level, meanwhile, the enamel floating ball allows the top end of the sleeve to always stay below the water level, and therefore a solar water heater can discharge water even if the water level is low.