Anode rod: The anode rod in your water heater can cause your hot water to smell bad/worse than your cold water. If you have a magnesium rod it can react with dissolved sulfate to form H2S, which smells like rotten eggs and can be detected by the human nose at part per billion levels. Simply removing your anode rod, while it will mitigate/eliminate the problem, is a bad idea. It can, however, be replaced with an anode rode made of aluminum or zinc. If you keep your water heater at or above 150 °F, aluminum is your only choice.
If your cold water also smells of H2S, replacing the anode in your water heater will not help.
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