A heater producing smelly water is an everyday problem we have all encountered. There is hardly a person who has never come across the notorious rotten egg odor that heaters tend to produce sooner or later. It results from the reaction of anaerobic bacteria which lives in the water inside the heater and the magnesium or aluminum of its sacrificial anode (i.e. the metal rod in the heater tank which protects it from corrosion). The suggestions below will, hopefully, help in removing this noxious odor.