When your garbage disposal hums but doesn’t work, you may assume it’s broken. You may think you’ll need to pay for a plumber or a new unit, but thankfully there are many steps you can follow to get it working again.
To fix a humming and not working garbage disposal, you should first unjam any food by using a wrench. Check for circuit trips, lubricate the blades, and then clear any drainage blockages. After this, your unit is probably broken and you’ll need a replacement.
I have put together 5 actionable steps to get your garbage disposal working again, and have given easy-to-follow instructions for each step. I’ve started with the most likely causes of humming garbage disposals and ruled out all potential issues – let’s get into it.
5 steps to get your garbage disposal working & not humming
1. Unjam your disposal
The most likely cause of garbage disposals humming but not working is jammed objects. Note that this is the cause of most issues with garbage disposals.
The first thing I recommend you do is to clear any kind of blockage. There are a couple of methods of doing this – some people online will say to stick your hands into the blades and pull out food. But I wouldn’t recommend that as it’s potentially dangerous and ineffective.
If the unit suddenly started humming and not working, you should first allow it to cool down. You can do this by simply running cold water and waiting for 15 minutes. Then follow these instructions:
- Disconnect the garbage disposal from the power source. This prevents electric shock.
- Underneath the garbage disposal is a hexagonal screw that you can turn to release food jams. Use a 1/4-inch hex key in place of the wrench. Rotate it clockwise and counterclockwise to release the jam.
- Go back to the top of the garbage disposal and use a utensil or wooden broom to rotate the grinding plate at the bottom of the disposal.
- Rotate the disposal wrench or hex key again to ensure the jam has been alleviated.
- Then reconnect the garbage disposal to the outlet, turn on the circuit breaker, and test out the functionality of the garburator again.
Hopefully, this fixes the humming, but if not I have a few other effective and useful suggestions that I’ll take you through step-by-step.
2. Reset the circuit (GFCI and circuit board)
The second thing you should do is check for any tripped circuits. A tripped circuit could be causing your garbage disposal to hum but not work. This could mean the unit is only receiving residual electricity. Follow these instructions:
tripping circuit board
Check your circuit board cupboard to see if your garbage disposal has tripped the circuit. This is only relevant if your garbage disposal is hardwired into your system. If it has been tripped, flick the switch back to ‘on’. Then try resetting your garbage disposal and testing to see if it works.
Note: There are many reasons why a reset button may also not work and I wrote another article on how to fix a garbage disposal reset button.
Garbage disposals are more often wired into a GFCI plug socket. If your GFCI has tripped, try resetting it (press the red RESET button). Then test to see if the garbage disposal comes on again.
Fingers crossed once you’ve unjammed any stuck objects and checked for tripped circuits your garbage disposal stops humming and starts working! But if not I have a few more tips and tricks you should continue trying…
3. free up the blades
Dish Soap has saved me hundreds of dollars over the years and it has many plumbing applications in the home. If you’ve unjammed your disposal and reset the circuit, the next most likely cause is stiff blades or a seized motor. This could be causing your unit to hum but not work, and this little trick might just do the job…
Put a generous amount of dish soap into the sink basin. Then manually spin the blades using a utensil or the hex wrench beneath the unit. Then try turning the unit on again. Fingers crossed this alleviates the humming and the motor turns on.
Note: I never bother with buying disposal cleaning tablets. Dish soap is cheaper and just as effective.
If it did work, the dish soap lubricated either the blades or the motor. Whilst this will get you back up and running, it may not bode well for the life of your garbage disposal.
Garbage disposal blades commonly become rusty after a few years and whilst dish soap may have worked for now, it’s possible your garbage disposal unit is nearing the end of its life. This process may have bought you a few more weeks or months’ worth of usage.
If this didn’t work, move on to step 4 where I’ll help you unclog your pipes…
4. Un-clog your pipes
Another possible cause of the garbage disposal humming but not working is a clogged drain. This is different from a blocked garbage disposal – here I’m talking about the actual drain underneath the garbage disposal.
Where there is a blockage your garburator may not be able to push down waste and it could cause a humming but no functionality. It’s also possible the drain blockage is slight enough to let through water, but is blocked sufficiently to cause your unit to hum.
Use a plunger
The easiest method to unblock the drain underneath the garbage disposal is to use a plunger. Lots of people think plungers are just for the toilet, but actually, they are effective for kitchen sink blockages too.
Use it in the same way – place the cup of the plunger around the sink drainage, and firmly pump up and down for around 20 seconds. Be careful not to use too much force though – you could end up dislodging the sink from the surface.
Un-do the waste pipes underneath the sink
Hopefully, the plunger unblocked the drain but if not, you’ll need to un-do the P-trap beneath the sink. Make sure you have a bucket handy before undoing any plumbing pipes.
Most plumbing drainage these days is undoable with your hands. Remove the P-trap by loosening the washer nut. Inspect for any blockages and if so, hit the pipe down into the bucket to dislodge.
If you don’t find any blockages, you’ll need to remove the waste pipe above the P-trap. Repeat the same process.
Note: To get rid of the dirty bucket of waste, pour the water down the toilet and put the food waste into the bin. You don’t want to clog your toilet!
Hopefully one of these four steps has fixed your garbage disposal, but if not move onto step 5. Although you’ll need a new unit, things might not be as bad as you imagine…
5. Your motor is toast
Garbage disposals only last about ten years, but I’ve seen many cheaper units only lasting a couple of years. Unfortunately most of the time you suspect there’s internal damage and you’ve ruled out everything else, the only option is to replace the unit.
It’s tough to say what exactly may have caused your garbage disposal to break, but it could be rust build-up, cracked o-rings, or a burnt capacitor/starter motor. Even simple things like loose bearings aren’t fixable – garbage disposals are sealed units making them near impossible to repair.
So in my opinion, if you’ve ruled out jammed blades, or a faulty circuit, you’ve lubricated it and the pipes aren’t clogged then it’s a waste of money to phone a plumber. Here are some tips on replacing your garbage disposal, and it’s not as bad as you might think:
- It’s not that difficult to replace a garbage disposal unit as a DIY job, even if it might seem like a big job. There are loads of great Youtube tutorial videos out there and Garbage Disposal units (on Amazon) are now really cheap.
- I’d recommend buying the same brand of garbage disposal as you currently have, ensuring the mounting brackets are the same. No need to replace the drain if it’s still good.
- Remember to take pictures of your old set-up before dismantling. Then you’ll know how to re-install the new unit. Also, if you need to buy plumbing drainage pipes, take the piece that connects to the disposal to your hardware store to ensure you’re buying the right parts.
Here’s a great video on how to replace your garbage disposal: