Quick answer: First exclude an emergency: if a fuel-gas leak is possible, leave immediately and call your gas supplier or 911 from outside. Do not operate switches or inspect appliances. For a non-emergency disposal odor, food residue may be involved; InSinkErator links odors to food buildup and insufficient water flow. Follow your exact model’s maintenance instructions without putting a hand through the disposal opening. Ask the manufacturer if safe access is unclear, and ask a licensed plumber about persistent sewer-like odors.
A sewer smell rising from the kitchen sink is hard to ignore, and it’s easy to assume the worst. Most of the time, though, the cause is right at the top of the disposal: food scraps rotting where you can’t see them. Less often, the smell really is sewer gas coming up the drain. Here’s how to tell which one you have, how to clean the disposal the way its makers recommend, and when to call a plumber.
First: is it sewage, food, or gas?
An unexplained rotten-egg smell can indicate a fuel-gas leak. If you suspect a leak, leave the building immediately, regardless of how strong the smell seems. Do not search for the source, inspect appliances, operate switches or appliance controls, use a phone inside, or light or extinguish flames. From outside and away from the suspected leak, call your gas supplier or 911. Stay out until emergency responders say it is safe. CPSC instructs people who suspect a gas leak to leave immediately and call for help from another location. Use the cleaning table and steps below only after gas-leak and other emergency concerns have been excluded.
| What you notice | Most likely cause | Where to start |
|---|---|---|
| Smell is strongest right at the disposal opening and gets worse after you use it | Food buildup under the baffle and in the grind chamber | Steps 1 to 4 below |
| Disposal drains slowly or water backs up into the sink | A clog in the disposal or drain | Step 5 |
| Smell came back after a trip, or the sink is rarely used | A dry P-trap letting sewer gas through | Step 6 |
| Other drains in the house smell too | A dry trap elsewhere, a blocked vent, or a plumbing leak | “If it still smells” below |
| The tap water itself smells like rotten eggs | Something in the water supply, not the disposal | FAQ below |
Why a garbage disposal smells like sewage
Trapped food. InSinkErator says food particles can build up in the grind chamber and on the baffle over time. That’s the rubber flap set in the sink opening. Affresh, a Whirlpool cleaning brand, points to the splash guard and inner surfaces as places where food debris collects and bacteria grow, which can cause musty or sour smells.
Grease. Fats, oils, and grease congeal as they cool, coating the inner walls and leading to clogs and odors over time, Affresh says.
Not enough water. InSinkErator links odor to insufficient water flow during and after use, and Affresh notes that grinding too much food at once or the wrong foods can cause clogs.
Sewer gas. The curved pipe under a sink, the P-trap, holds a little water that blocks sewer gases from coming back into the house. The South Davis Sewer District, a public utility in Utah, explains that this water can evaporate when a drain isn’t used regularly, letting sewer gas escape.
What you need
- Rubber gloves and a flashlight
- A scouring pad, or a dish brush you’ll keep only for this job
- Dish soap
- Baking soda (about 1/4 cup) and a sink stopper
- A lemon or orange cut into wedges (optional)
- Tongs or pliers, for pulling out anything stuck in the opening
How to clean a garbage disposal that smells like sewage
Safety: Never put your hand into a garbage disposal, even when it’s switched off. InSinkErator repeats this in its odor instructions. Turn off the disposal and disconnect the power, either by unplugging it under the sink or switching off its circuit breaker, before you clean around the opening.
Step 1: Cut the power
Switch off the disposal, then unplug it or turn off the breaker. Use tongs or pliers, not your fingers, if you see anything stuck in the opening.
Step 2: Scrub the baffle
Do not put a hand through the disposal opening or into the grind chamber. Check your exact model’s manual to see whether the baffle is designed for user removal and how to remove it safely. If removal and external cleaning are explicitly permitted, follow those instructions with the power disconnected. Do not assume that another model’s removable-baffle instructions apply. If cleaning would require reaching through the opening, stop and ask the manufacturer or a qualified service professional.
Step 3: Flush with baking soda and warm water
Put the stopper in, fill the sink about halfway with warm water, and mix in 1/4 cup of baking soda. Restore the power. Then turn on the disposal and pull the stopper at the same time, so the water rushes through and carries loose particles away. This is InSinkErator’s own method.
Step 4: Freshen with citrus (optional)
InSinkErator says grinding citrus can help neutralize odors. Cut a lemon or orange into wedges, turn on the disposal with a steady stream of cool water, and feed the wedges in one at a time. The rinds help clean the grinding parts. Ice cubes can help scrub them too, but InSinkErator notes ice usually melts before it cleans the whole chamber. Also, its disposals don’t have blades, so ice won’t “sharpen” anything.
Step 5: Deal with grease or a slow drain
For greasy buildup, Affresh suggests adding 1/2 cup of baking soda, letting it sit for 30 minutes, then adding 1 cup of vinegar. Let it fizz and soak for 10 minutes, then run cold water through the disposal. If the sink still drains slowly or backs up after cleaning, follow your disposal’s manual for clearing a jam, or call a plumber. InSinkErator advises against putting harsh cleaning products down a disposal, so skip chemical drain openers.
Step 6: Refill the trap if the sink sat unused
If the smell showed up after you were away, or the disposal is in a sink you seldom use, run water for a minute to refill the P-trap. The South Davis Sewer District suggests running water in every sink, shower, and floor drain at least once a month, and pouring a cup or two of water into drains you rarely use.
If it still smells: when to call a plumber
If the odor is still there after a thorough cleaning and a refilled trap, the problem is probably in the plumbing rather than the disposal. The South Davis Sewer District says lingering odors after refilling drains can mean a damaged trap, a blocked vent, or a plumbing leak, and that a licensed plumber can find and fix it. The same applies if you see water under the sink, the smell spreads to other rooms, or the disposal leaks.
Don’t mix cleaners
When a smell is bad, it’s tempting to pour in everything at once. Don’t. Poison Control warns that mixing bleach with an acid, such as vinegar, creates chlorine gas, and that bleach should never be mixed with ammonia. If a commercial cleaner has already been used, do not add another product or a homemade mixture. Follow that product’s label and ask its manufacturer or Poison Control for product-specific advice; flushing with water is not a universal guarantee that switching cleaners is safe.
How to keep the smell from coming back
- Run cold water every time. InSinkErator recommends a moderate flow of cold water while grinding and for a few seconds after. Avoid hot water while grinding, though it’s fine to drain hot water between uses.
- Keep grease out. Never pour fat or grease into the disposal or drain. Affresh suggests letting grease solidify in a jar or can and throwing it away.
- Feed it in batches. Smaller amounts grind and flush more easily, Affresh says.
- Know what your model can handle. InSinkErator says its Standard Series models shouldn’t get stringy or fibrous foods like banana peels, celery, or rhubarb. Affresh recommends keeping eggshells, coffee grounds, potato peels, pasta, and bones out. Check your own manual.
- Clean it monthly. Affresh suggests a monthly cleaning for most households, plus extra cleaning after greasy meals or strong-smelling foods like onions or fish.
- Use it regularly. InSinkErator notes that frequent use helps clear food scraps from the chamber.
FAQ
Why does my garbage disposal smell like sewage even after cleaning?
If the baffle and chamber are clean, look past the disposal. A dried-out P-trap, a blocked plumbing vent, or a leak can let sewer gas into the kitchen, according to the South Davis Sewer District. Refill the trap first. If the smell continues, call a plumber.
Is the sewage smell from a disposal dangerous?
Smell alone cannot establish safety. An unexplained rotten-egg odor may indicate fuel gas: leave immediately without operating switches, inspecting appliances, using a phone inside, or manipulating flames. Call your gas supplier or 911 from outside and away from the suspected leak, and do not reenter until responders give permission. If anyone has trouble breathing or other severe symptoms, call 911 from a safe location.
My dishwasher drains into the disposal. Could that be the source?
It can work both ways. A smelly disposal can make the dishwasher smell, and a dishwasher drain hose without a high loop can let dirty water back in. Our guide to a dishwasher that smells like rotten eggs covers the drain hose, air gap, and the knockout plug in new disposals. For a musty smell in the dishwasher itself, see dishwasher smells like wet dog.
What if the water from the faucet smells like rotten eggs?
Then the disposal isn’t the cause. The Minnesota Department of Health says hydrogen sulfide gas can give water a rotten egg taste or odor. It suggests smelling the water from the hot and cold faucets after you’ve been away for a few hours to narrow down the source.
Can I pour bleach or drain cleaner down the disposal?
InSinkErator advises against harsh cleaning products in its disposals. Follow your exact model’s care instructions, never put a hand through the disposal opening, and never combine cleaners or assume that a rinse makes switching products safe.
Sources
- CPSC: Certain Older Gas Connectors May Be Dangerous
- CPSC: Carbon Monoxide, Fire, and Gas-Leak Safety
- InSinkErator – There’s an Odor Coming From Garbage Disposal
- InSinkErator – How to Clean Garbage Disposal
- InSinkErator – Frequently Asked Questions
- Affresh – Garbage Disposal Smells: Common Causes and Simple Fixes
- South Davis Sewer District – Understanding Sewer Odors and P-Traps
- Connecticut PURA – What To Do If You Smell Natural Gas
- Minnesota Department of Health – Hydrogen Sulfide and Sulfur Bacteria in Well Water
- Poison Control (poison.org) – Chlorine gas: What happens if you mix bleach and other cleaners
Last reviewed: October 13, 2026. Always follow your disposal’s manual and manufacturer instructions.
Editorial note, October 19, 2026: Six specified sections received a limited safety maintenance update; this was not a complete revalidation of this article.