the heater or water draining from the heater when the heater is opened while still installed when the heater must be opened for servicing such as for draining or otherwise removing any mineral sediments cleaning scale built up on the heating element 22 and the inner walls of the heater or changing either of the thermostat 24 or the heating element 22 the liquid communication to and from the heater 12 is cut off using valves 32 and 34 the bottom lid 42 is conveniently unscrewed and any water contained in the external tank 12 is drained due to the small capacity of the water heater 12 during the opening of the bottom lid 42 only a minimal amount of water is spilled unlike the copious amounts of water spilled when the flanged sleeve nuts are loosened on the water heater tanks in the prior art yet another advantage is in the compactness of the water heater 12 rendering same simple and quick to install into the existing old solar panel collector heating systems this case would typically call for removal of the flanged sleeve supporting the old heating element and thermostat sealing the existing water heating tank thereby converting the existing main storage tank into the tank 4 in one embodiment of the invention the heating element and the thermostat if both relatively clean or having been cleaned of mineral scale can be removed from an existing deployed water storage tank and installed in the water heater 12 thus easily forming the system of the invention by retrofit there is seen in fig3 a water heating and storage.