Abstract: A water pre-heating arrangement, incorporating with a water heating system including a water heater, includes a heat exchanger for guiding water to flow from a water source to a water tank, and a solar energy collecting device having a solar energy collecting surface mounted to the heat exchanger wherein the solar energy collecting surface is adapted for collecting and transforming solar energy into heat energy to increase a water temperature in the heat exchanging unit so as to pre-heat the water in the heat exchanging unit before entering into the water tank. Therefore, the water heater powered by a fossil fuel heats up the water in the water tank from the pre-heated temperature to a predetermined temperature while being energy effective.