Why is My Garbage Disposal Leaking?

by Paul

A common problem among garbage disposals users is when there is a garbage disposal leakage. If you are looking for answers to why is my garbage disposal leaking and how to fix it, here I’m going to share the most usual reasons and easy fixes.

It certainly is an irritating issue yet usually not very serious. Unless, of course, the runny water causes molds, pest, and insects under your kitchen sink. Don’t worry, you can fix it by yourself. It creates a mess when there is a garbage disposal leaking water under your sink. You just need to know where to look for the leak and know how to fix it.

Where & Why is My Garbage Disposal Leaking

There is an easy way to find the location from where your garbage disposal is leaking.

  • Step 1:
    Unplug the disposal unit. Before starting any type of maintenance work with your garbage disposal, you must always remember to switch off the unit.
  • Step 2:
    Place a bucket under the sink.
  • Step 3:
    Take a glass of water and put few drops of food color in it.
  • Step 4:
    Now pour the water into the sink.
  • Step 5:
    Check underneath the sink to find out the exact location where the water is leaking.
  • Step 6:
    Fix the problem following the below instructions. Now repeat the process again to check if the leakage is completely fixed.

How to Fix a Leaking Garbage Disposal?

Before you go to repair the disposal unit, you need to know what causes the usual leakages. 

If you know the place where your garbage disposal is leaking from, then read the below situations to know what can cause the leakage.

Common Areas to Look for Leaking Garbage Disposal

In a very typical scenario, you will find the leak comes from any loose connection of different parts of the disposal unit. So, you should check the connected areas first. To find out the answer of why is the garbage disposal leaking, these are common areas you should look for:

1. Sink Flange

Sink flange is the neck area of the garbage disposal. It is the part that attaches your disposal unit with the sink. If the installation is not done properly, you can discover water leaking from sink flange. On the other hand, after a long time of use, the sink flange can get loose and let water leak from that place.

Fix: In this case, you need to check few things.

  • First of all, get a wrench and check the mounting bolts if those are tight enough. Tighten all the screws one by one and check if still the garbage disposal leaking water. Rather than using the regular three bolt mount system, many disposals use different types of mounting nowadays. For any other type of mounting you need to check if the connection is loose and fix it following your disposal manual.
  • Most of the time during installation, you need some plumbers putty to seal the mounting connections. Over time when the putty gets old, this seal can break and leak water. So you should check if the leak is happening because of old putty.

In this case, you need to do a lot more work than just tightening the bolts. First of all, remove the disposal unit from the mounting. Then remove the mounting from the sink. Now re-install your disposal unit with some new fresh putty.

Other plumbing issues may be the cause and checking our guide "How to Troubleshoot General Plumbing Problems" might help.

If the leak is small and you think there is no need to remove the entire disposal unit then simply put some fresh putty to seal the leaking area.

  • If your disposal is few years old, then there is a chance of rust and corrosion, which can cause a broken flange. In this case, you need to remove your disposal completely and change the old flange with a new one. Don’t forget to check if the garbage disposal is still leaking.

For a more detailed instructions on removing your unit, read "How To Remove A Garbage Disposal".

2. Gasket

Beside a sink flange, a disposal gasket can also be the most usual cause for a garbage disposal leaking water. If your garbage disposal is leaking from the top, then do not forget to check the rubber gasket. Rubber gaskets seal the mounting to the flange. Over time a gasket gets old, and the rubber gets oversized. Sometimes it can develop leak or cracks, and it then is unable to maintain the tight seal with the mounting.

Fix: You need to replace the old gasket with a new one. Before going to buy a new gasket make sure you know the model of your disposal unit. Many disposal units have different size of gaskets though those belong to the same brand.

Steps to change a rubber gasket:

  • You can easily find the gasket for your garbage disposal unit from a home improvement store. It will not cost much. Make sure you know the exact brand and model number of your garbage disposal before going to the store.
  • Before doing any kind of work with a garbage disposal make sure your disposal unit is unplugged. Now disconnect the drain hose along with the dishwasher hoses.
  • Remove the garbage disposal from the mounting. If you need more information you can check How To Remove a Garbage Disposal.
  • Remove the old gasket from the mounting and place the new gasket at the same spot.
  • Reinstall the garbage disposal and all the connecting pipes.
  • Don’t forget to check the disposal unit if it still leaking water.

3. Dishwasher Connection

Dishwasher connection

A garbage disposal usually contains a dishwasher connection. It allows the dishwasher leftovers to get chopped and drained through the pipeline.

A loose connection or a leak can occur in between the two hose pipes. If your dishwasher is connected to the disposal unit, then you must check if the leaking water is coming from the connecting pipe.

Fix: The garbage disposal port is connected to the discharge pipe of the dishwasher with a metal clamp. Tighten the metal clamp and check if the runny water stopped. If not, then you must check for a broken or cracked hose. In that scenario, you have to replace the whole hose line.

4. Loose Drain Lines

A very common place to look for a leaky garbage disposal is the drain line connection. One connection is what I already mentioned a dishwasher connection. Another is a larger pipe that comes out from the lower part of the disposal and its connected to the sewer pipes.

This is the pipe that disposes the chopped-up food and water from your disposal unit to the drain line. If the hose connection is loose, then you can see water running out from the pipe connection.

Fix: These two pipes care connected with rubber gasket or screws. If it is connected with screws, try to tighten up the bolts. If it is related to a rubber gasket, check if the gasket got old and ruined. Replace the rubber gasket and check if still water runs or not.

5. Disposal Leaking from Bottom

If your garbage disposal is leaking from the bottom, then it is not a good sign. Try to find out if there is any leakage from the upper outside part that is causing the water. If not then, most probably the disposal unit is old enough to cause a broken seal inside. Consider replacing the unit if you find out you have a disposal leaking from the bottom, especially when it’s old.

Sometimes, it is seen that the disposal is leaking from the reset button. If the unit is relatively new, then you much check warranty and send the unit for a repair. If the unit is old, consider replacing it with a new one. You may consider repairing the reset button, but certainly, it will not run for a longer period.

So, these are the common solutions for how to fix a leaking garbage disposal. Hope you got the solution for your “Why is My Garbage Disposal Leaking?” problem. I’d suggest doing the fix by yourself, if you need to save the plumber’s cost. If your disposal is quite aged, then consider buying a new unit rather investing and wasting money on it.