Informational Guide

Garbage Disposal Water Comes Back Up

It’s frustrating when you’re using your garbage disposal and water comes back up. We will explain the causes and how to fix it.

by Holly Curell

Garbage disposals are one of the most underrated pieces of equipment in your home. They allow you to safely dispose of food substances and help to protect your pipes so everything keeps flowing as it should.  

Unfortunately, even the most purchased garbage disposal brands can develop issues, and sometimes garbage disposal water comes back up from your sink. This could mean there's an underlying problem, and it needs to be dealt with immediately. In this guide, we'll help explain why this happens and what you can do to fix it quickly.  

Before we talk about how to fix the issue of garbage disposals spitting up water, it's important to understand why it happens. There are 3 main reasons why this occurs: 

Drain Blockage

The most common reason for water coming back up through your disposal is a blockage. This typically occurs when something unsuitable, like bones or plastic, has gone down through the disposal and stops the water flow.

This can also occur if there are too many food products, like potato peels, etc. which will block the system.  Before attempting to unblock the drain, make sure you understand how your garbage disposal works and have the proper tools.

Overuse Of Garbage Disposal

This is another common cause of water being thrown up, and it's linked to drain blockage. This can happen when you're using it too much, so food is blocking up in your system, or fats and oils are causing internal issues. Overuse of your garbage disposal can also impact the overall effectiveness of the machine, and it may need to be repaired.  

Was Not Installed Correctly 

Like any plumbing, you need your garbage disposal to be installed correctly to work correctly. You may find that your pipes are not connected properly or that a T-shaped connection has been used instead of a Y-shaped connection which is impacting drainage. If you think there's an issue with installation, you should ask a professional to take a quick look and make any adjustments necessary.  

garbage disposal water comes backp up

Garbage Disposal Water Comes Back Up (4 Ways To Fix It Yourself)

Once you've diagnosed the problem, you need to fix it quickly because it can make the whole sink unusable and even cause water to spread underneath your sink. This can eventually lead to dampness and mold if left untreated.  Thankfully, there’s a lot of standard household items you can use to unclog a garbage disposal. Here’s a quick breakdown: 

Plunger

This should be your first response if you notice a blockage in your garbage disposal. You need to make sure you have a sink plunger, not a toilet plunger, because otherwise, it won't work. Sink plungers don't have a long handle and should fit right around the sink. Then follow these steps: 

  • 1
    Fill the sink next to the garbage disposal with about 3-4 inches of water. Connect the garbage disposal and make sure it’s plugged in.  
  • 2
    Use your plunger on the opposite sink, making sure there's a vacuum seal. Pump until you can feel the suction underneath in the sink. After pumping 5-10 times, stop.  
  • 3
    Drain the sink next to the garbage disposal and then put the plug in. Unplug the garbage disposal and try to run water through the machine. If it still isn't flowing through as it should, then move on to the next step. 
  • 4
    Use your plunger on the sink with the garbage disposal and pump 5-10 times.  
  • 5
    Run water through the disposal again and see if there are any leaks. If it’s still not working, it means that the blockage is probably too far down, and the plunger technique won't work.  

Boiling Water 

One of the simplest and best ways to deal with a blockage is to use boiling water. You won’t need any equipment for this, but make sure you handle the boiling water carefully.  

  • 1
    Boil a full kettle of hot water 
  • 2
    Turn off your garbage disposal and remove it from the sink. Rinse the outside and look for any visible blockages which can be taken out.  
  • 3
    Pour the boiling water down through your sink, trying to get it all directly down the pipes. This should help to remove any debris and break up any blockages in the sink. Make sure you don’t pour this through the garbage disposal, or the boiling water can damage the mechanism.  
  • 4
    Reattach the garbage disposal and make sure it’s connected securely. Run water through the machine to see if there are any blockages or if there’s any water spitting back.  

Baking Soda & Vinegar Mixture 

This technique is similar to the boiling water method, and it's another effective home remedy to remove blockages in your pipes. You’ll need baking soda, vinegar, and some protective gloves for this, as well as some towels to catch any liquid.  

  • 1
    Start by following the steps above and pouring boiling water down the drain.  
  • 2
    Then, mix 1 cup of baking soda with 1 cup of vinegar to create an acidic solution that is intended to dissolve any blockages. Pour this directly down the drain, making sure your garbage disposal is disconnected, so it doesn't flow through it. 
  • 3
    Cover the drain for about 10 minutes while the solution does its work.  
  • 4
    Finish by pouring more boiling water down the drain to wash out any blockages. 
  • 5
    Reattach your garbage disposal and run water through it to see if there is still any spitting. Hopefully the problem is now resolved.  

Plumber’s Snake 

This is a slightly more technical way to stop the garbage disposal from flowing back up, but it will be needed if the blockage is too far down for other methods to be effective. You will need a plumber's snake for this, pliers, and towels to catch any moisture from the pipes. 

  • 1
    Clear the cabinet from under the sink, so you have free access to the garbage disposal and the pipes behind it.  
  • 2
    Find the U-shaped pipe underneath the sink. This is the trap, and it will either be a P-shaped or S-shaped trap. Use pliers to loosen and remove the threaded plug at the bottom.  
  • 3
    Check for any visible dirt or debris which might be blocking the pipe. Remove whatever you can reach.  
  • 4
    Remove the vertical tailpiece underneath the sink and rinse off. Remove any debris or blockages from the pipe.  
  • 5
    If there's still no visible blockage, then remove the trap from the main drainpipe at the back of your cabinet.  
  • 6
    Insert the plumber’s snake into the pipe and use the handle to extend it down into the drain. Keep going until you can feel you hit the blockage and then wind the plumber’s snake back in to remove the blockage. You can review our guide on how to use a plumber's snake if you need assistance.
  • 7
    Reattach all the different components and use the pliers to make sure everything is securely in place.  
  • 8
    Run water through the disposal and make sure there are no leaks.  

How To Avoid Garbage Disposal Water Coming Back Up (Prevention Tips)

The best way to stop water coming back up through your garbage disposal is to take preventative measures. If you look after your garbage disposal properly, you shouldn't have any issues, and you won't need to spend time and effort unblocking it. Here's what you should do to avoid any blockages: 

Understand What Not To Put In Your Garbage Disposal 

The number one cause of issues with garbage disposals is putting the wrong things down them. You can find a complete list of what not to put in a garbage disposal here, but as a brief summary, you need to avoid: 

  • Egg Shells 
    These may seem like a natural biodegradable food, but they can block the machine, and fragments can get lodged within the disposal itself. 
  • Starchy Foods 
    Potatoes or pasta are very starchy, and this can cause serious issues for your machine. The thick starch can cause garbage disposal water to come back up, and you're better off putting it in a food compost bin. 
  • Fibrous Foods 
    Onions, celery, and asparagus are very fibrous, and as the food breaks down in the disposal, it can lead to blockages. Avoid putting them down the sink if at all possible. 
  • Oils And Fats 
    It can be tempting to drain oil down your sink, but if it gets into your disposal, it can really mess up the machinery. Over time, layers of fat and grease will build up and cause a nasty blockage in your pipes.  

Clean Your Pipes 

It would be best if you kept your garbage disposal and the connecting pipes clean. The easiest way to do this is to disconnect your garbage disposal and clean it in the sink. Look for any visible dirt or debris which could lead to blockages, and if necessary, let it soak overnight.

Once a week, you should pour a pot of boiling water through your pipes to get rid of any built-up grease or dirt that might cause future issues. 

egg shells

People Also Ask (FAQs)

How do you unclog a sink with a garbage disposal with standing water?

If your sink has standing water in it, then it's completely clogged. You'll need to disassemble the P-trap underneath the sink by removing the nut with some pliers and then lifting it away. This will allow the water to flow out of the sink, but make sure you have a bucket or bowl to catch the liquid.  

When should I empty my garbage disposal? 

You should empty your garbage disposal whenever you realize there's a big chunk of food or debris which might block the machine.  

Are you supposed to clean a garbage disposal regularly? 

Yes, to properly maintain and clean your garbage disposal, you should look to clean it every week. 


Conclusion

garbage disposal is a vital piece of equipment in a modern kitchen, but you need to maintain it properly to avoid blockages which can lead to water spitting back up into your kitchen.

Hopefully this guide has helped you understand why this happens and given you helpful information on dealing with the problem quickly and effectively.  

Holly Curell is the editor extraordinaire for Plumbing Lab. Having grown up in Michigan, Holly has spent time living in New York, Virginia, & currently North Carolina, where she lives with her husband & family. Holly loves DIY & has years of experience with at-home plumbing problems that arise from having 3 kids & living in colder climates. When she's not writing about her plumbing knowledge, Holly enjoys reading, hiking & relaxing with family.

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