Sulfur odors in homes are typically caused by sulfate and bacterial growth in pipes, hot water heaters or water lines. Sulfur odor can also be caused by raw sewage, so it is always important for homeowners to consult with a plumber to ensure accurate diagnosis and prompt repair.
Sulfate bacteria is not considered dangerous to homeowners, but the bacteria can create a gas that can be toxic in high levels. Sulfate bacteria is caused by a variety of factors that include rotting food, chemical reactions and naturally occurring sulfur in underground soil that creates sulfuric emissions in ground water. Sulfur gas is similar in scent to rotten eggs and is often detected in hot and cold water faucets. If the odor is only emitting from treated water, this often points to bacterial development within a water-softening device.