Shower smells like rotten eggs

Symptoms

• Smell noticeable mainly when water runs or drain is used
• Smell is strongest with hot water
• Household is on well water
• Smell fades between uses but returns

Likely causes

• CommonBacteria buildup in the drain producing hydrogen sulfide gasOrganic buildup (soap, skin, hair) in the drain or trap can host odor-causing bacteria.
• CommonWater heater anode rod reacting with sulfur bacteria in the waterThis is especially common with well water and shows up mainly in hot water.
• PossibleDry P-trap letting sewer gas throughIf a drain isn't used often, the water seal in the trap can evaporate, allowing gas smells up.
• PossibleSulfur naturally present in well waterSome groundwater sources simply contain sulfur compounds regardless of plumbing condition.

What to do

1. Note whether the smell is stronger with hot water only, cold water only, or from the drain when no water is running.
2. If it's from the drain, clean it thoroughly with a bottle brush and a baking soda and vinegar flush, then rinse well.
3. If a drain is rarely used (like a guest bathroom), run water for a minute weekly to keep the trap filled.
4. If the smell is only in hot water, this often points to the water heater anode rod reacting with the water.
5. For a suspected anode rod issue, flush the water heater and consider having the anode rod inspected or replaced.
6. For well water households, consider a water test for sulfur bacteria and iron/sulfate levels.
7. If the smell resembles a gas leak (natural gas or propane) rather than sulfur from water, treat it as a gas emergency instead.

Tools and parts

• Bottle brush
• Baking soda
• White vinegar

When to call a pro

Call a plumber or water treatment specialist if flushing doesn't help, especially for a suspected anode rod or well water bacteria issue.

Safety