Quick Answer:
If your kitchen smells like rotten food after replacing a disposal, start by cleaning the rubber splash guard, rinsing the grinding chamber, and flushing the unit with a strong stream of cold water while running the disposal briefly. Sniff at the drain opening and inside the cabinet to find where the smell is coming from, and check the trap to make sure it still holds water after a few hours. If basic cleaning and isolation don’t help, call a pro.
Why This Happens
New disposals can pick up odors for a few common reasons:
- Food debris trapped under the splash guard or left in the grinding chamber during installation.
- Installation debris, grease, or leftover packaging material caught in the drain line.
- Plumbing issues nearby—backflow or cross-connections that let wastewater or sewer gases near the sink. See Cross-flow after disposal install for more on that type of problem.
- A leaking connection or a dry trap that allows sewer gas into the cabinet rather than the drain.
Step-by-Step What to Do
1. Turn off power
Before you touch the disposal, switch it off at the wall and unplug it or flip the circuit breaker. Never stick your hand into the disposal with power on.
2. Clean the splash guard and rinse the grinding chamber
Pry up the rubber splash guard (the round flap in the sink) and wash it with warm soapy water or a 50/50 vinegar-and-water mix. Use a small brush or old toothbrush to remove trapped particles. Reach into the chamber only after power is off and remove any visible debris or packaging bits, then rinse the chamber with water.
3. Flush with strong cold water while running briefly
Turn the cold water on at full flow and run the disposal for 15–30 seconds. Cold water helps move solids through the blades and down the drain without producing steam that can carry odors back up. Keep the run time short to avoid stressing a new unit.
4. Sniff to isolate the source
With the sink dry, sniff directly at the drain opening and then inside the cabinet under the sink. If the smell is stronger inside the cabinet, the issue may be a leak, trapped debris, or a dry trap. If it’s at the drain, the splash guard or grinder chamber is the likely source.
5. Confirm the trap holds water
Let the sink sit unused for a few hours, then look down the drain to confirm a small pool of water remains visible in the trap (the P-trap). If the trap has gone dry or leaks out, sewer gases can come up and smell like rotten food.
6. Repeat cleaning if needed and run water after each test
Repeat steps 2 and 3 if you still smell something. After any cleaning, flush with cold water again and check whether the odor fades. If the smell converts to a sharp chemical or bleach scent, stop and ventilate the area.
What Not to Do
- Don’t pour bleach or harsh chemicals into a smelly disposal to “sanitize” it—fumes can be harmful and strong chemicals can damage seals, pipes, and the disposal’s components.
- Don’t run the unit dry or put your hand inside while it is still connected to power.
- If odor persists despite normal drainage and cleaning, don’t keep pouring chemicals or trying risky fixes yourself—professional inspection may help identify hidden problems.
When to Call a Professional
Call a plumber if:
- The smell continues after cleaning the splash guard and flushing the unit.
- You find standing water or a leak under the sink, or the trap won’t hold water.
- You suspect installation problems such as backflow or a persistent connection issue. If you see signs of leaking or persistent odors that aren’t solved with the basic checks, a plumber can diagnose issues like improper venting or whether the unit is incorrectly installed—this can relate to disposal leaks days after install.
Safety Notes
- Always disconnect power before reaching into the disposal.
- Use gloves and eye protection when cleaning to avoid contact with food waste or residue.
- Use only mild cleaners or a vinegar-and-water solution. Strong acids or bases can corrode plumbing and harm seals.
Common Homeowner Questions
- My new disposal smells right away—how long until it’s normal? Short answer: Most installation smells fade after a few cleanings and runs of cold water; persistent odors after that need further checks.
- Can I run hot water to clear the smell? Short answer: No—use cold water. Hot water can loosen grease and let it travel farther into the drain where it can re-solidify and smell.
- Is it normal to have some water in the cabinet? Short answer: No—puddles or dampness indicate a leak and should be inspected promptly.