Hydrogen Sulfide

Hydrogen sulfide is released when naturally occurring sulfate is degraded by bacteria in groundwater. Hydrogen sulfide gas produces on offensive "rotten egg" or "sulfur water" odor and taste in the water. In some cases, the odor may be noticeable only when the water is initially turned on or when hot water is run. Heat forces the gas into the air which may cause the odor to be especially offensive in a shower. The offensive odor of hydrogen sulfide gas generally makes testing unnecessary. Most people recognize the smell and proceed to correct the problem.

If hydrogen sulfide odor is associated primarily with the hot water system, a hot water heater modifications may reduce the odor. Replacing the water heater's magnesium corrosion control rod with one made of aluminum or another metal may improve the situation. Hydrogen sulfide may also be reduced or removed by shock chlorination, activated carbon filtration, oxidizing filtration or oxidizing chemical injection.

Finally, both sulfates and hydrogen sulfide are both common nuisance contaminants and neither is considered a significant health hazard.

Reference: University of Nebraska