Short answer
First run the water for a minute. The P-trap under the sink holds water that blocks sewer gas, and in a sink nobody uses it dries out. If it still smells, pull the stopper and clean off the gunk. Pour half a cup of baking soda and a cup of white vinegar, wait 15 minutes and flush with hot tap water. Scrub the overflow hole too. If several drains smell, call a plumber.
Safety first
Never mix bleach with vinegar, ammonia or drain cleaner: together they make toxic gas. If you smell rotten eggs near the stove, furnace or water heater and not at the drain, leave the house and call your gas company from outside.
How to get rid of a smelly sink drain
1A bad smell comes up from the drain
It may smell like sewer or like something rotten. The cause is almost always in the first foot of pipe.
Read all the steps
- A bad smell comes up from the drain. It may smell like sewer or like something rotten. The cause is almost always in the first foot of pipe.
- Run water for a minute to refill the trap. The curved pipe under the sink keeps a little water that blocks sewer gas. In a sink nobody uses, that water dries out.
- Pull the stopper and clean off the gunk. Hair, soap and toothpaste stick to the stopper and rot. Lift it out, wipe it clean and rinse it.
- Baking soda, vinegar, then hot water. Pour half a cup of baking soda, then a cup of white vinegar. Let it fizz 15 minutes and flush with hot tap water.
- Scrub the overflow hole. The little hole near the rim gets slime inside. Clean it with a bottle brush and rinse. Fresh again.
- Still not fixed? Call a plumber Especially if: several drains in the house smell at the same time.
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Kitchen sink with a garbage disposal
The smell often comes from food stuck under the rubber splash guard. Unplug the disposal or switch off its breaker, lift the flaps and scrub under them with an old toothbrush. Then run cold water and grind a handful of ice cubes and a few citrus peels.
What not to do
- Do not pour drain cleaner to fix a smell. It does not clean the stopper or the overflow, and it can burn you.
- Do not pour boiling water into plastic pipes: it can loosen the joints. Hot tap water is enough.
- Do not cover the smell with air freshener. If the trap is dry, sewer gas keeps coming in.
When to call a plumber
- Several drains in the house smell at the same time.
- The drain gurgles or bubbles when another fixture drains (the vent may be blocked).
- The smell comes back within days, even after cleaning.
- Sewage backs up into a sink, tub or floor drain.
Frequently asked questions
Why does my bathroom sink smell like sewer?
Usually the P-trap dried out, or the stopper and the overflow are coated with rotting gunk. Run the water first, then clean both.
Does baking soda and vinegar work on drain smells?
It helps loosen the slime that causes most smells, and it is safe for pipes. It does not clear real clogs, a dry trap or a blocked vent.
How do I keep a guest bathroom sink from smelling?
Run the water for a minute once a week. That refills the trap before it dries out and lets sewer gas in.
Can a smelly drain make you sick?
A quick whiff is not dangerous, but you should not breathe sewer gas for days. Fix the source and air out the room.
Why does my sink smell like rotten eggs?
Bacteria in the drain make a sulfur smell. If the rotten egg smell is away from the drain and near a gas appliance, it may be gas: leave and call your gas company.