Quick Answer:
If the rotten-egg smell is only at the kitchen sink, it’s usually coming from the drain, the garbage disposal, or a dried or dirty trap — not the water supply. Do a quick smell test with a glass of tap water to confirm whether the odor is in the water itself or coming from the drain, then follow a few simple cleaning and inspection steps before calling a pro.
Why This Happens
Common reasons for a sulfur or rotten-egg smell localized to the kitchen sink:
- Food, grease, or biofilm trapped in the drain or garbage disposal that produces hydrogen sulfide gas as it breaks down.
- A P-trap that has partially dried (rare in a used kitchen sink) or is clogged and holding decomposing material.
- Residue in the sink stopper, strainer, or around the rim where bacteria grow.
- Less commonly, the problem could be related to plumbing work or seasonal changes that allow odors into the line — see Rotten smell after winterization for similar scenarios.
- If multiple fixtures smell, or the smell is strong throughout the house, the issue may be a sewer line problem or a venting issue.
Step-by-Step What to Do
Step 1 — Isolate the smell: test the water
Pour water from kitchen tap into a glass and smell it away from the drain. If the water in the glass smells like sulfur, the supply or water heater may be the cause. If the glass does not smell, the odor is coming from the drain or disposal.
Step 2 — Run water and flush the trap
Run hot tap water for 30–60 seconds and then run the cold for a short burst. This refills or flushes the P-trap and can clear small amounts of trapped debris or grease that trap odors.
Step 3 — Check and clean the garbage disposal and stopper
- Run the disposal with cold water for 30 seconds. Put a few ice cubes and a small wedge of lemon in the disposal and run it briefly to knock loose food and freshen the unit.
- Remove and clean the sink stopper or strainer. Scrub with dish soap and an old toothbrush to remove trapped residue.
Step 4 — Manual drain cleaning
If the smell continues, remove the U-bend (P-trap) only if you are comfortable doing so. Place a bucket underneath, undo the slip nuts, and check for trapped gunk. Rinse the trap and reassemble. If you’re not comfortable, skip this and call a plumber.
Step 5 — Quick surface clean
Scrub the sink basin, rim, and tailpiece with warm soapy water. Rinse well and run water down the drain to push any loosened debris into the sewer line.
Step 6 — Observe and repeat if needed
After cleaning, run the faucet and disposal several times over the next day. If the smell returns or if you notice gurgling, slow draining, or odor from other fixtures, move to the professional step below.
What Not to Do
- Do not pour chemicals into kitchen traps. Harsh drain cleaners can damage pipes, kill beneficial bacteria that help break down waste, and create hazardous fumes when mixed with other cleaners.
- Do not stick your head directly into the drain to sniff; prolonged inhalation of sewer gases can be harmful.
- Don’t remove plumbing parts or attempt repairs you’re not trained for — improper reassembly can cause leaks or larger problems.
When to Call a Professional
Call a plumber if any of the following apply:
- The smell persists after cleaning and flushing, or it returns quickly.
- Multiple fixtures produce the odor, or you have slow drains and gurgling sounds.
- You detected a sulfur smell in the glass of tap water during the test, or you have concerns about water quality — this may need a water professional or utility check. Also contact a plumber if the issue appeared after recent work on your plumbing, as in cases similar to Sulfur smell after plumbing repair.
- There are signs of a sewer backup, such as sewage in drains, or strong indoor sewer gas that makes people feel sick.
Safety Notes
- Ventilate the area well while working. Open windows and run a fan if possible.
- Wear gloves and eye protection when cleaning drains or removing the P-trap.
- Avoid mixing cleaning agents. Never mix bleach and ammonia or other cleaners; dangerous gases can form.
- If anyone feels dizzy, nauseous, or has headaches from the smell, leave the house and seek fresh air. Call emergency services if symptoms are severe.
Common Homeowner Questions
- Is the smell dangerous? Short-term low-level sulfur smell is usually unpleasant but not life-threatening; strong or persistent sewer gas exposure can be harmful and should be addressed quickly.
- Can I fix this without a plumber? Often yes — cleaning the disposal, stoppers, and P-trap can solve sink-only smells. Call a plumber if the smell persists or involves multiple fixtures.
- Will pouring bleach down the drain help? Bleach may temporarily mask odors but won’t remove the source and can be harmful if mixed with other cleaners; it’s not a recommended long-term fix.
For more related articles, see the Sulfur / Rotten Egg Smell in Water hub.