why does hot water stink?
The incidence of rotten egg odor or black water in hot water lines is due to the reaction of. sulfates and micro-organisms in the water that create Hydrogen Sulfide (H2S). This is a water. chemistry condition, rather than a water heater problem.
The odor of hydrogen sulfide gas can be detected in water at a very low level. Smell the water coming out of the hot and cold water faucets. Determine which faucets have the odor. The rotten egg smell will often be more noticeable from the hot water because more of the gas is vaporized.