Key Takeaways
- Press the red reset button under the unit first — it trips constantly and takes 5 seconds.
- Humming but not grinding = jammed. Free it with a hex key from the bottom, never your hand.
- Disposal runs but the sink backs up? The clog is past the disposal — usually the P-trap. Clean it (procedure below).
- Run cold water 20 seconds after grinding — it keeps grease moving instead of coating your pipes.
- Never feed it: grease, coffee grounds, eggshells, oatmeal, pasta, rice, fibrous vegetables.
Why Is My Garbage Disposal Not Working?
The three most common causes are a tripped reset button, a jammed flywheel, or a clog downstream in the P-trap. Work through the fixes below in order — they resolve nearly every “dead disposal” call we get in Denver.
Fix 1: Press the Reset Button
Push the small red reset button on the bottom of the unit. Disposals trip their internal breaker at the slightest overload — a fork, a bottle cap, even a heavy load of potato peels. If it clicks and stays in, run cold water and test. If it trips again immediately, move to Fix 2.
Breaker-labeling trick: while you’re under the sink, check your panel — if the disposal’s breaker isn’t labeled, label it now. You’ll thank yourself next time.
Fix 2: Free a Jam (Humming But Not Grinding)
A humming disposal with no grinding means the flywheel is jammed — free it with a 1/4-inch hex key in the bottom socket.
- Confirm the wall switch is OFF.
- Find the hex socket in the center of the unit’s underside.
- Insert the hex key and work it back and forth until the flywheel turns freely.
- Remove the key, press the reset button, run cold water, and flip the switch.
Never put your hand inside the disposal — not to “feel” the jam, not ever. The hex key exists so your fingers don’t have to.
Fix 3: Check for Power
No hum at all? Check the breaker panel and the outlet. Disposals on the same circuit as dishwashers trip breakers more often than you’d think. If the breaker is fine and the outlet has power (test with a phone charger), but the unit is completely dead, the motor has likely failed — that’s a replacement, not a repair.
Disposal Runs But the Sink Still Backs Up — Why?
If the disposal grinds fine but water won’t drain, the clog is downstream — almost always in the P-trap or the drain arm. The disposal did its job; the pipe after it didn’t.
Fix 4: Plunge the Sink (6–8 Pumps)
- Plug the disposal side with a stopper (or have someone hold a wet rag over the other basin if it’s a double sink).
- Fill the problem side with 2–3 inches of water.
- Use a sink plunger (flat cup, not a toilet flange plunger) and pump firmly 6–8 times.
- Pull the plunger on the last upstroke to break suction.
Fix 5: Clean the P-Trap
The P-trap is the U-shaped pipe under the sink — it catches everything the disposal misses.
- Place a bucket under the trap and put on gloves.
- Unscrew the two slip nuts (usually hand-tight; channel-locks if stubborn).
- Dump the trap’s contents into the bucket and scrub it out.
- Check the short horizontal drain arm going into the wall — poke it clear with a bottle brush.
- Reassemble hand-tight plus a quarter turn. Run water and check for drips.
If water flows freely after this, you’re done. If it still backs up, the clog is deeper — time for a drain cleaning pro.
How Do I Deodorize a Smelly Disposal?
Baking soda + vinegar + time + boiling water. Denver’s hard water leaves mineral film on the rubber splash guard — the #1 source of disposal odor.
- Pour 1/2 cup baking soda into the disposal.
- Follow with 1 cup white vinegar. Let it fizz for 10–15 minutes.
- Boil a full kettle and pour it through while running the disposal with cold water.
- Scrub the underside of the splash guard with an old toothbrush — that’s where the slime lives.
Skip the lemon-peel myth as a “cleaner” — it perfumes; it doesn’t clean. For routine upkeep, see our garbage disposal cleaning guide.
What Should Never Go Down a Garbage Disposal?
| Never feed it | Why |
|---|---|
| Grease, oil, fat | Solidifies in pipes — the #1 cause of kitchen clogs |
| Coffee grounds | Clump into a dense sludge that packs the trap |
| Eggshells | Membrane wraps around impellers; grit settles in pipes |
| Oatmeal, pasta, rice | Expand with water into a starchy paste |
| Fibrous vegetables (celery, artichokes, corn husks) | Fibers tangle the flywheel |
| Bones, pits, shells | Dulls impellers and trips the reset |
The 20-second rule: run cold water (never hot — hot melts grease, which then re-solidifies downstream) for 20 seconds after grinding stops. It flushes everything fully into the main line instead of letting it settle in your trap.
DIY vs. Calling a Plumber in Denver
| Symptom | DIY-safe | Call a pro |
|---|---|---|
| Tripped reset | Press it, test | If it trips repeatedly |
| Jammed flywheel | Hex key from below | If it won’t budge |
| Slow drain, disposal runs | Plunger, P-trap cleaning | If backup persists past the trap |
| Leaking from the unit body | Tighten mounting ring | If it leaks from the housing — replace |
| Dead, no power, breaker fine | — | Motor failure — replacement time |
| Frequent clogs across fixtures | — | Possible main-line issue — camera inspection |
Thinking replacement? See typical garbage disposal installation costs before you decide.
Frequently Asked Questions
How long do garbage disposals last?
8–12 years with normal use. Frequent resets, persistent odors you can’t clean away, and leaks from the housing itself all signal end of life.
Can I put drain cleaner in my garbage disposal?
No — chemical drain cleaners corrode disposal seals and splash back dangerously. Use the mechanical methods above instead.
Why does my disposal smell even when it’s clean?
The rubber splash guard. Its underside grows a biofilm that the grinding chamber never touches. Scrub it with a brush and dish soap — the smell usually vanishes immediately.
Is it worth repairing a leaking disposal?
Only if the leak is at the sink flange or dishwasher connection (fixable seals). A leak from the unit’s housing means internal failure — replace the unit.
Do I need an electrician or a plumber to replace a disposal?
A plumber. Disposal replacement is plumbing work (drain connections, dishwasher hookup); the electrical is a simple cord/plug or hardwire swap a plumber handles routinely.
Still stuck? Professional Plumbers Denver repairs and replaces all major disposal brands across the metro — upfront pricing, licensed and insured. Call (720) 390-2652, 24/7.
