Hydrogen Sulfide in New England Water

Hydrogen Sulfide and Rotten Egg Smell in Water

The presence of a rotten egg smell in water is a common water quality issue in the New England region, typically caused by hydrogen sulfide (H2S). Hydrogen sulfide is a colorless gas that can naturally exist in groundwater. Sulfur-reducing bacteria in groundwater use sulfur as an energy source to convert sulfates to hydrogen sulfide, releasing the unpleasant odor.

These bacteria thrive in oxygen-deficient environments, often found in deep or shallow wells, and can also reside in plumbing systems.

Hydrogen sulfide can also enter surface water through springs, especially in shale and sandstone areas. Its occurrence is often associated with groundwater with low pH and high levels of iron and/or manganese, which are other typical water quality issues in New England.

Hydrogen sulfide has a pungent smell at low concentrations, and is detectable by most people above 0.03 parts per million (ppm). The United States EPA has not established a Maximum Contaminant Level for hydrogen sulfide in water.

Health Effects of Hydrogen Sulfide in Household Water

In concentrations present in household water, hydrogen sulfide usually does not pose a health risk. However, at high concentrations, it can be flammable and poisonous, potentially causing adverse health effects in confined areas.

While the sulfide smells detected in water wells are primarily from bacteria and generally not at levels harmful to health, sudden onset of a rotten egg odor should be examined by a water filtration professional to rule out sewage pollution.

In addition to its odor, hydrogen sulfide can be corrosive, leading to the leaching of metals from plumbing systems into the water. This corrosion can result in a black precipitate that stains laundry and bathroom fixtures, darkens silverware, and discolors copper and brass utensils.