Where the smell comes from
The rubber splash guard at the top of the disposal is the most common source. Its underside collects a film of food and grease that you never see from above. Bits of food can also cling to the grinding chamber walls and the turntable, especially if the unit is run briefly with little water.
Sometimes the disposal is not the source at all. A partially clogged trap or kitchen drain line holds standing waste water that sours quickly in warm weather. And in some cases a dry or poorly vented drain lets sewer gas reach the sink. Those smell different, more like sewage than rotting food, and need a plumber to sort out.
A safe cleaning routine
Do this with the power off for every step that involves reaching near the unit.
Cut the power
Switch off and unplug, or turn off the breaker.
Clean the splash guard
Lift or flip the rubber flaps and scrub the underside with a brush and dish soap. Some guards pop out for cleaning.
Scrub the visible chamber
Use a long-handled brush, not your hand, on the chamber walls you can see.
Grind ice
Restore power and grind a tray of ice cubes with cold water running to knock residue off the grinding parts.
Flush
Run cold water for a minute after each use going forward.
Habits that keep odors down
- Run cold water before, during and for a while after grinding.
- Grind small amounts at a time rather than a full sinkful.
- Keep grease and cooking oil out; wipe pans and put the grease in the trash.
- Do not let food sit in the disposal overnight.
- Clean the splash guard regularly.
- Skip chemical drain cleaners, which can damage parts.
Smell type and likely source
| Smell | Likely source | What to do |
|---|---|---|
| Sour, rotting food | Splash guard and chamber residue | Clean as above |
| Rancid, greasy | Grease buildup in the disposal or trap | Clean, and stop putting grease down |
| Sewage or rotten eggs | Trap, vent or drain line issue | Call a licensed plumber |
| Comes back within a day | Standing water in a slow drain | Have the drain checked |
When it is worth a service call
If cleaning does not help, or the smell is clearly sewage, a plumber can check the trap, the drain line and the venting. In older Fullerton homes, kitchen drains may be original cast iron that has built up a rough interior where grease clings. The cost depends on what they find: cleaning a trap is a small job, while clearing or inspecting a drain line is a bigger one. Ask what they recommend and why, in writing.
Questions to ask
- Is the smell coming from the disposal, the trap or the drain line?
- Is the sink drain vented properly?
- Is there grease buildup in the line that should be cleared?
- Would a camera look at the kitchen line help?
Common questions
Do citrus peels help a smelly disposal?
Small pieces may freshen the smell briefly, but they do not clean the splash guard. Large or fibrous peels can also cause jams.
Can I pour bleach into the disposal?
Harsh chemicals are hard on seals and can be dangerous if mixed with other cleaners. Soap, a brush and ice are safer.
Why does it smell worse in summer?
Warm temperatures speed up the breakdown of food residue and any standing water in the drain.
General information for Fullerton, not a quote or professional advice. In an emergency, call 911.