Why Does Only One Sink in My House Smell?
Why Does Only One Sink in My House Smell Like Rotten Eggs?
If you've noticed a foul, sulfur-like smell—often compared to rotten eggs—coming from just one sink in your home, you're not alone. This odor can be alarming, but in most cases, it’s a localized issue with an identifiable cause and straightforward solution. At Clean Water Ohio, we help homeowners throughout Central Ohio understand and eliminate water-related odors so they can get back to enjoying clean, fresh water.
Here’s what could be causing the smell—and how to fix it.
What Causes the Rotten Egg Smell?
The rotten egg smell is typically caused by hydrogen sulfide gas. This gas can be naturally present in some water supplies—especially in well systems—or it can be produced by bacteria that feed on sulfur compounds in the water or plumbing system.
If the smell is only coming from one sink, the cause is usually isolated to that specific faucet or drain area rather than your entire water supply.
Common Reasons Why Only One Sink Smells
1. Dirty or Dry P-Trap
The P-trap under your sink is designed to hold water and block sewer gases. If a sink hasn’t been used in a while or if the trap is partially clogged, bacteria can grow and release foul-smelling gases into your home.
2. Bacteria in the Faucet Aerator
The small screen on the end of your faucet (called an aerator) can trap debris, sediment, and bacteria. When water flows over this buildup, it can release unpleasant odors.
3. Contaminated Faucet Components
Pull-out sprayers, cartridges, or internal faucet parts can trap small amounts of water. Over time, bacteria can grow in these stagnant areas, producing a noticeable smell when the water is turned on.
4. Biofilm in the Drain
If the smell is stronger when water isn’t running—or lingers after the water is off—it might be coming from the drain. Organic material in the drain line can host bacteria that emit sewer-like odors.
5. Localized Plumbing Issue
In rare cases, plumbing issues such as poor venting or cross-connections can allow sewer gases to enter through one specific fixture.
Step-by-Step Fixes
You can often resolve this issue without needing a plumber. Here’s how:
1. Flush the P-Trap
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Run hot water for a few minutes.
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If the sink hasn’t been used in a while, pour a few cups of water down the drain to refill the trap.
2. Clean the Faucet Aerator
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Unscrew the aerator at the tip of the faucet.
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Soak it in vinegar to dissolve mineral deposits.
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Scrub with an old toothbrush, rinse, and reinstall.
3. Sanitize Faucet Hoses or Sprayers
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For faucets with pull-out sprayers, sanitize the hose by running a vinegar solution through it or following the manufacturer’s cleaning instructions.
4. Disinfect the Drain
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Pour a mixture of baking soda and vinegar down the drain, followed by boiling water. This helps kill odor-causing bacteria in the drain line.
5. Call for Water Testing
If the smell persists, especially with warm water or other sinks starting to show symptoms, your water may contain hydrogen sulfide or sulfur-reducing bacteria that require treatment.
Prevent Future Odors
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Use all sinks regularly, even if only for a few seconds a week.
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Clean faucet aerators every few months.
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Sanitize faucet components annually or as recommended.
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Install a whole-home filtration system if water quality is a recurring issue.
Clean Water Ohio Can Help
At Clean Water Ohio, we offer free water testing and professional-grade water treatment systems from AO Smith and WaterCare. If you’re dealing with smelly water—whether it’s one sink or your whole house—we can identify the root cause and recommend a lasting solution.
Don’t ignore that rotten egg smell. Even if it seems like a small issue now, it could be a sign of a larger problem with bacteria, plumbing, or your water source. Let our team help you make sure every faucet in your home delivers clean, odor-free water.
Schedule your free water test today with Clean Water Ohio and take the guesswork out of your home’s water.