A smelly garbage disposal is almost always food residue and grease clinging to the rubber splash guard, the chamber walls and the drain beyond. The underside of the splash guard is the usual culprit. Scrub it with a brush, grind ice and rock salt, flush with baking soda and hot water, and finish with citrus peel. Turn the disposal off at the wall before you reach near it.
Safety first
Switch the disposal off at the wall switch and, if there is a plug under the sink, unplug it. Use tongs or a long-handled brush to reach inside, not your fingers. Never use bleach and vinegar together, or any chemical mix, in the drain, because the fumes can be harmful.
Scrub the splash guard
- Turn off the power
Switch off the wall switch and unplug the unit if you can.
- Scrub both sides of the rubber flap
The black rubber guard hides slime on its underside. Use an old toothbrush or a bottle brush, dish soap and hot water.
- Rinse well
Run the tap and wipe the flange around the opening.
Clean the chamber
- Add a cup of ice and a half-cup of rock salt
Run the disposal with a strong flow of cold water. The ice scours the walls and the salt gives it some abrasion.
- Pour in baking soda and hot water
Sprinkle about half a cup of baking soda into the disposal and flush with a kettle of hot (not boiling) tap water, which loosens grease. Wait ten minutes.
- Grind citrus peel
A lemon, orange or lime peel run through the disposal with cold water leaves a fresh scent. It is a freshener, not a cleaner, so do it after the steps above.
Dishwasher detergent pods and bleach are not recommended inside a disposal.
Deodorize the drain
If the smell lingers after the chamber is clean, the P-trap and drain line beyond are coated. Pour a stream of hot water and dish soap down, and clean the trap if you can; see kitchen sink clogged: how to clear it. Leaving the water running for 30 seconds after use helps flush the pipe.
When the smell is not the disposal
| Smell | Where else to look |
|---|---|
| Smell appears when the dishwasher runs | Dishwasher drain line or filter — see dishwasher smells bad and dishwasher smells like sewage |
| Sewer-like smell even with a clean disposal | Dry trap or a venting problem — see sewer smell |
| Smell with slow draining | Partial clog in the drain line |
Prevention
Run cold water for 15 to 30 seconds before and after using the disposal, grind small amounts at a time, and give it a weekly ice or citrus clean. Avoid leaving food sitting in the basin.
What not to put in a disposal
Grease and oil, fibrous or stringy food such as celery and corn husks, eggshells in large amounts, starchy foods like rice and pasta, coffee grounds in bulk, and bones all contribute to buildup and smells. If the disposal is jammed or humming, see garbage disposal jammed and humming but not spinning.
When to call a plumber
If the smell persists after a deep clean, if the disposal leaks, or if the sink drains slowly, a plumber should inspect the disposal, trap and drain. An old disposal with a rusted or cracked chamber is better replaced than repeatedly cleaned.
