A smelly garbage disposal is usually food stuck under the rubber splash guard and around the top of the grind chamber, left there because the disposal was run with too little water. Disconnect the power, scrub the underside of the splash guard, flush the disposal with baking soda and water the way InSinkErator directs, and run cold water every time you grind. If the smell is sewage rather than rotting food, it is usually not the disposal at all.
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Handy for upkeep: a foaming disposal cleaner that reaches under the splash guard. Check Glisten Disposer Cleaner on Amazon
What the Smell Tells You
- Rotting food, strongest at the sink opening: food buildup on the underside of the rubber splash guard and around the top of the grind chamber. InSinkErator says a disposal odor is usually this, caused by too little water running during and after use. Fix it with the cleaning steps below.
- Worse after the dishwasher runs: dirty dishwasher water may be backing up the drain hose. See dishwasher air gap vs high loop.
- Sewage or sewer gas, not food: that usually is not the disposal. A dry trap or a venting problem lets sewer gas into the room; see sewer smell in the house. If it is a rotten-egg smell from the hot water, see why water smells like rotten eggs.
- Musty smell in the cabinet, or damp wood: something under the sink is leaking. See garbage disposal leaking.
How to Clean a Smelly Garbage Disposal
These steps follow InSinkErator’s own instructions for an odor. You need a scouring pad and baking soda.
- Disconnect the power. Unplug the disposal under the sink or switch off its breaker. The wall switch alone is not enough.
- Clean the splash guard and the top of the chamber. Many splash guards lift or twist out (see our splash guard guide); if yours does, scrub it at the sink. If it does not, scrub the underside of the guard and the upper lip of the grind chamber through the sink opening with a scouring pad, as InSinkErator directs. Keep your hand out of the grind chamber; InSinkErator says never to put your hand in the disposal.
- Flush it with baking soda. Put the stopper in, fill the sink halfway with warm water and mix in 1/4 cup of baking soda. Restore power, then turn the disposal on and pull the stopper at the same time so the water washes the loosened food away. If the stopper no longer seals, see which stopper fits your disposal.
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Keep It From Coming Back
- Run a moderate flow of cold water while you grind, and keep it running for a few seconds after grinding stops. InSinkErator says to avoid hot water while grinding; draining hot water between uses is fine.
- Never pour grease or fat into the disposal or the drain.
- If the splash guard is torn or stays slimy after cleaning, replace it. Our splash guard guide covers the replacements, and which splash guard fits matches the guard to your disposal’s brand and series.
Parts That Fix It
Each part below was sold or shipped by Amazon, new and in stock, when we checked on September 23, 2026; details come from each Amazon listing.
- A foaming disposal cleaner. Glisten Garbage Disposer Cleaner, lemon, 4 packets: the listing says the foam scrubs the disposer’s sidewalls, blades and the underside of the splash guard, and suggests weekly use to prevent buildup. It is a maintenance step, not a substitute for scrubbing the guard when it is already caked.
When to Call a Licensed Plumber
- The smell is sewage, and it comes from more than one drain or keeps coming back after the traps have water in them.
- Several fixtures drain slowly or gurgle at the same time, which points to the main line, not the disposal. See clogged drain vs main line.
- There is water under the sink you cannot trace to a connection you can see.
- The disposal still hums, trips its breaker or will not power on after the reset and jam steps in garbage disposal not working; wiring problems belong to an electrician.
FAQ
Why does my garbage disposal still smell after I cleaned it?
The usual culprit is the underside of the rubber splash guard, which a quick rinse misses. If the guard is clean and the smell is sewage rather than food, check for a dry trap or a dishwasher hose backing up; those smells are not coming from the disposal.
Should I run hot or cold water through a garbage disposal?
Cold while grinding. InSinkErator says to run a moderate flow of cold water during grinding and for a few seconds after, and to avoid hot water while grinding food waste. Draining hot water between uses is fine.
How often should I clean a garbage disposal?
Whenever it starts to smell, and on a routine if yours does often. InSinkErator does not give a schedule; the Glisten cleaner’s listing suggests weekly use to prevent buildup.
Why Trust Plumbing Picks
Plumbing Picks is written by a Journeyman Plumber — State of Georgia Licence #JP507711 — and the license is verifiable through the Georgia Secretary of State’s license verification portal. The steps on this page follow the manufacturer sources listed below, and product details come from the Amazon listing, not from hands-on testing. Nobody pays to be included here. Where a link goes to Amazon we may earn a commission at no extra cost to you. More on who writes this and how we pick.
Sources
Bottom Line
Most disposal smells come from food caked on the underside of the splash guard. With the power off, scrub it and the top of the chamber, flush with warm water and baking soda, then grind with cold water from now on. A foaming cleaner like Glisten helps keep it clean. A sewage smell is a different problem: check the trap, the dishwasher hose and the vent before blaming the disposal.