Quick Answer:
If you deep-cleaned the sink but the odor is back the next day, the smell is most likely coming from the drain path (stopper/strainer, overflow channel) or from trap water that has evaporated or been siphoned out. Check whether the smell returns after you use the sink or even when it sits, remove and clean the stopper/strainer area, flush any overflow channel, and then run water for a full minute to refresh the trap water.
Why This Happens
Common reasons the odor comes back after cleaning:
- Residue and bacterial film collect below the visible bowl—especially around the stopper, strainer and the overflow channel.
- The P-trap’s water can evaporate or be slow to refill, letting sewer air through. That’s often why you notice a return after the sink sits.
- Food bits trapped in a garbage disposal or under the stopper can produce persistent smells. For a related situation, see Smell after grinding meat as an example of trapped food causing lingering odor.
Step-by-Step What to Do
1. Identify when the odor returns
- Note the pattern: does the smell come back immediately after you use the sink, or only after the sink has been unused for hours? This tells you whether it’s trapped food or trap water loss.
- Test quickly: clean the visible bowl, run a minute of water, then stop using the sink overnight. Check in the morning and after a single use to compare.
2. Remove and clean the stopper/strainer area
- Remove the stopper or lift out the strainer (follow the manufacturer method if needed).
- Use a small brush or old toothbrush and a mild cleaning solution (dish soap and warm water) to scrub the stopper, the underside, and the visible drain opening. Rinse thoroughly.
- If you have a garbage disposal, run it with running water and a little dish soap, and clear any trapped debris with a brush—never put your hand into the disposal.
3. Flush the overflow channel (if present)
- Overflow channels can hold old, smelly water. Pour a cup or two of warm soapy water into the overflow opening, then brush if you can reach it with a flexible brush or a small bottle brush.
- Follow by rinsing with clear water to push loosened material out into the drain.
4. Refresh the trap water
- Run cold water at the sink for a full minute so the P-trap refills and any loosened debris moves down the line. A full minute ensures the trap has a good seal against sewer air.
- If you have multiple fixtures, run nearby fixtures briefly to ensure traps are all holding water.
5. Final check
- After cleaning and running water for a minute, stop using the sink and check again after a few hours and the next morning. If the smell is gone after you run the water but returns when it sits, trap evaporation or a slow leak may be the issue.
What Not to Do
- Don’t keep re-cleaning the bowl only—focus on the drain opening, stopper/strainer, and overflow path.
- Don’t ignore a persistent smell; if odor persists despite cleaning and fresh trap water, professional inspection may help.
- Don’t pour unknown chemical mixtures down the drain or mix strong cleaners (for example, bleach and ammonia).
When to Call a Professional
Call a plumber if:
- The odor remains after you’ve cleaned the stopper/strainer, flushed the overflow, and refilled the trap by running water for a full minute.
- You detect strong sewer gas, multiple fixtures smell, or you hear gurgling or slow draining—these can mean a venting problem or a partial blockage down the line.
- You suspect a leaking or damaged trap (water level in the trap won’t stay) or sewer connection issues.
Safety Notes
- Wear gloves and eye protection when you reach into drains or handle cleaners.
- Do not put your hand into a garbage disposal; always disconnect power before trying to retrieve objects.
- Avoid mixing cleaning chemicals. If you use a commercial drain cleaner, follow the label and ventilate the area.
Common Homeowner Questions
- Sink smells only in morning? — Often the trap water evaporates overnight; run cold water for a full minute and clean the overflow and stopper.
- Will bleach stop the smell? — A short bleach rinse can help surface bacteria, but it won’t reach gunk under the stopper or in the overflow; physical cleaning is also needed.
- Can I fix it myself or do I need a pro? — Try the steps above first; call a professional if the smell persists, comes from multiple fixtures, or you hear gurgling or notice slow drains.
For more related articles, see the Odors Originating from Bathroom Sink Drain hub.
For more related articles, see the Food Waste Odors & Bio-Buildup hub.