How to Unclog a Garbage Disposal Like a Plumber

When something that should not be put in the garbage disposal ends up being put there, it either jams it or clogs it. A clogged garbage disposal will either be draining slowly, or backing up when fully clogged resulting in standing water in the unit.

Use of insufficient water to drain the garbage disposal or grinding foods rich in starch like pasta, potato and/or banana peels are the biggest contributors to clogged garbage disposals. Fats, greases and oils are also notorious. Foreign objects like silverware can also jam the blades, preventing them from grinding and draining away waste.

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Whenever you have a humming garbage disposal, it is usually a sign of jammed blades. In this case the disposal is not necessarily clogged, and freeing up the blades will be enough to have it working again, grinding and draining properly.

With a clogged garbage disposal, the clog is hardly inside the unit itself but in the drainpipe or P-trap. If you have a double bowl kitchen sink, the sink bowl not connected to the garbage disposal could also be the one causing the clog since they share the same P-trap and drainpipe.

The fastest way to unclog a garbage disposal is to disconnect and clean the P-trap and then install it back. Alternatively, clamp off the dishwasher drain hose and use a plunger to dislodge the clog. A baking soda and vinegar combination is also very effective in breaking down clogs. Follow it up with a gallon of boiling water.

How to Unclog a Garbage Disposal

The first thing to do before trying to troubleshoot a slow draining or clogged garbage disposal is turn off the power to the unit. Another thing to remember is to never stick your hand inside the garbage disposal.

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Garbage disposal blades have speeds of up to 2000 revolutions per minute and can therefore cause serious bodily harm.

To successfully and quickly unclog a garbage disposal, always look for signs that can point you to where the clog is coming from. Here are some of the signs:

  • If you have a double bowl sink and both sinks are clogged, the clog is most likely in the P-trap.
  • When you have a double bowl sink but only the sink connected to the garbage disposal is backing up, the clog is in the garbage disposal itself or its drainpipe, just before the P-trap.
  • If the garbage disposal is not working but humming, something is jamming the blades.
  • When you have a dishwasher that is also draining slowly, the problem is in the dishwasher drainpipe or P-trap.

Here are the different methods of unclogging a garbage disposal starting with the easiest one:

1. Free up the Blades

If you have a clogged or slow draining garbage disposal that is also humming, the blades are not spinning freely. Turn off its power and inspect the status of the blades.

  • Grab a flashlight and carefully inspect the inside of the garbage disposal. Check for foreign objects that could be impeding the free rotation of the blades. If you see anything pull it out with a pair of tongs.
  • Use an Allen wrench to manually rotate the motor. Garbage disposals usually come with an Allen wrench. Stick it at the slot underneath the garbage disposal and spin the motor manually. If you don’t have that Allen wrench you can use any other wrench as long as it fits.
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  • Check the status of the reset button (also underneath the disposal). If it has tripped it will have popped out. Press it in to reset it.
  • Turn on the power to the garbage disposal and carefully listen and watch if it is grinding and draining normally.

In some instances, this is usually enough to fix a slow draining or clogged garbage disposal.

2. Use a Plunger

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Plunging is one of the best methods of unclogging a garbage disposal with standing water. It uses the water to create hydrostatic pressure that pushes against the clog and in the process dislodge it.

To effectively plunge and unclog a garbage disposal, there are certain things you need to do upfront. The first thing is clip off the dishwasher drain hose if your disposal is connected to a dishwasher.

Failure to do that will send the wastewater from the disposal back to the dishwasher. While that on its own is disgusting, it will also reduce the amount of pressure pushing against the clog and you will have little success unclogging the garbage disposal.

If you have a double bowl kitchen sink, plug off the sink and overflow drain of the sink not connected to the garbage disposal. The reason for this is that if the clog is in the P-trap, the pressure will escape through the drain and overflow and you will be unable to unclog the garbage disposal.

When you have taken care of the above issues, it is time to get down to work.  Here is how to properly plunge a clogged garbage disposal:

  • Fill the sink with water up to the ¼ level. In order to plunger effectively, the base of the plunger cup has to be fully immersed in water to prevent pressure loss.
  • Position the plunger over the sink drain.
  • Start plunging. The first plunge should be a gentle one, to engage the plunger to the sink drain. Plunge aggressively after that without lifting the plunger off the sink drain.
  • Lift off the plunger from the sink drain after 2 minutes of plunging and check if the water is draining out. If not plunge some more.

You will know that the disposal has be unclogged when water from the sink is draining out freely. Turn on the garbage disposal and check if it is grinding and draining optimally.

3. Use Baking Soda and Vinegar

Baking soda and vinegar are fantastic in unclogging a slow draining garbage disposal. When combined, the 2 substances react very quickly and in the process break down clogs in the disposal drain and P-trap and unclog the disposal as a result.

Not only is baking soda and vinegar helpful in unclogging garbage disposals, they are also very efficient in getting rid of smells from the garbage disposals as well. You should actually pour little amounts of them in the unit from time to time to prevent smells, and also break down gunk, preventing them from causing clogs in the first place.

Here is how to unclog a garbage disposal using baking soda and vinegar:

  • Pour 1 cup of baking soda down the garbage disposal.
  • Slowly add 1 cup of vinegar and wait for 30 minutes.
  • Dump a gallon of boiling water down the sink.

If you are dealing with a slow draining garbage disposal. You can start with blasting hot water down the unit prior to the baking soda and vinegar, and then pour another amount after the 30 minutes.

While the baking soda and vinegar are quite effective in breaking down clogs, the hot water is very helpful in dissolving washing down the gunk down the drainpipe.

Since constant use of hot water in the garbage disposal in not encouraged, always dump a gallon of hot water in the sink not connected to the disposal from time to time. The hot water helps to avoids clogs and smells by dissolving and washing down waste down the drainpipe.

4. Clean the P-trap

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This is usually a the quickest and most effective method in unclogging a garbage disposal. Whenever you have a slow draining or backing up garbage disposal, the clog is usually located in the P-trap.

A P-trap is the U-shaped pipe under the kitchen sink. All the drains in your house have a P-trap, which also looks like an inverted P. P-traps have 2 main functions.

  • They hold a small amount of water at all times, preventing the sewer gases from coming up through the drain. Whenever there is a sewer smell in your kitchen most often the P-trap is usually empty.
  • They hold potential drain clogs, preventing them from clogging the drainpipe further away where it would be even harder to unclog.

In order to clean a P-trap, you will need to first disconnect it. Here is how to unclog a garbage disposal by cleaning the P-trap:

  • Place a bucket under the P-trap. There is always water and trash in the P-trap which can mess up your kitchen floor.
  • The P-trap has 2 connections, one higher and the other a bit lower. Start by disconnecting the lower connection so that water in the pipes can easily flow down to the bucket via gravity.
  • P-trap connections are usually hand tight. Attempt to loosen them with your bare hands and only result to a wrench if they are too tight.
  • Once the connections are loose, remove the P-trap and check how clogged it is. Bang it against a soft surface to remove out as much gunk as possible.
  • When most of the trash has been removed, drop it in a bowl full of vinegar to further clean it.
  • Check the pipe connecting the garbage disposal to the P-trap. Is it clogged/dirty as well? If that is the case, disconnect it from the garbage disposal using a flathead screwdriver and clean it as well.
  • Once clean, connect the garbage disposal drainpipe and P-trap back.
  • Turn on the garbage disposal and run it using cold water.

Most of the time this repair will fix any clogged garbage disposal. Make sure that the connections under the kitchen sink are tight and that there are no leaks.

To prevent garbage disposal from clogging, avoid grinding inorganic waste, foods rich in starch like pasta and potato peels, egg shells and coffee grounds. Fats, oils and grease should also never be dumped in the garbage disposal.

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