If your tap water smells like rotten eggs or sulfur, you’re not alone. This unpleasant odor is usually caused by hydrogen sulfide gas (H₂S) — a naturally occurring substance that can develop in your water supply for a few common reasons.
🛁 Common Causes of the Rotten Egg Smell in Water:
- Bacteria in the Water Heater
Sulfur-reducing bacteria can grow inside your water heater tank, especially if it’s been unused for a while or the temperature is set too low. These bacteria convert naturally occurring sulfur into hydrogen sulfide gas, releasing that foul odor when hot water is used. - Well Water Contamination
If you use well water, the smell may come from sulfur-reducing bacteria in the well system or groundwater. It’s a common issue in private wells, particularly in areas with high sulfur content in the soil. - Corroded Anode Rod
Water heaters contain a metal rod (usually made of magnesium or aluminum) that helps prevent tank corrosion. Over time, this rod can react with sulfur in the water and cause that “rotten egg” smell. - Municipal Water Reactions
Though less common, even city water can sometimes produce the odor when it reacts with plumbing components, particularly in older systems.
💧 Is It Dangerous?
In most cases, hydrogen sulfide in low concentrations is not harmful to your health, but it can damage plumbing, discolor silverware and fixtures, and make water unpleasant for drinking or bathing.
