Why is the Garbage Disposal Leaking?

When you see water dripping off the bottom of the garbage disposer you may think that it has to be replaced.  But that’s not necessarily true.

Sometimes the leak can be repaired.  The first step to making the repair/replace decision is to determine from where the leak is coming. 

Garbage disposer leaks usually come from one of five places:

  1. The sink flange — where the sink and the disposal unit directly connect
  2. The dishwasher hose connection— where the hose and the disposal connect
  3. The drain — where the drainage discharge pipe and the disposal connect
  4. The seals— water actually leaking from the very bottom of the disposal
  5. The motor housing– from a crack in the body of the disposal.

Before you decide about repair or replacement, determine the age of the disposal.  If it is a really old disposal unit, you may want to consider replacing it regardless of the source of the leak.  

When a disposal is replaced, the source of any leak on the old one will be repaired anyway, and tossing good money at an antique disposer that may present you with a second leak (or a motor or impeller failure) a short time later is probably not a good idea.

If you determine the disposer is worth salvaging, then the source of the leak has to be determined in order to find out if it can be repaired.  

Let’s go through all 5 leak sources and see what needs to be done to facilitate a repair (or if the repair is even possible).  

Let’s go through all 5 leak sources in your garbage disposal and see what needs to be done to facilitate a repair (or if the repair is even possible).  


1. The sink flange

If the sink flange is leaking, it can be removed and the leak repaired.  Most disposers have a dual sealing system for the sink flange.  

First, there is a ring of plumber’s putty installed between the sink flange and the sink surface.  

Second, there is usually a rubber gasket attached to the disposer which seals against the bottom of the sink when the disposer attachment flange is tightened.  

Putty is easily obtained at the hardware store and the gasket, if standard, is available there also.  If yours is a nonstandard gasket, one will have to be obtained from the manufacturer or his representative in the area.

The flange will either be removed by loosening a series of attachment bolts or with a quick connect fitting provided with the disposer. 

Beware that if the disposer is leaking here, corrosion may require extra effort or professional tools and skills to remove the flange.

2. Dishwasher hose connection

In some states, it is not legal to connect the dishwasher drain hose to the garbage disposer because of the risk of contamination of clean dishes and utensils.  

If your state allows this, then the hose may be connected to a barbed fitting that is molded into the grinder housing.  If it is leaking due to a loose or missing clamp which should be installed over the end of the dishwasher discharge hose, then a new clamp will do the trick.  

Be sure that the end of the hose is not cracked when you take it off the end of the fitting.  If the barbed fitting itself is cracked, then the disposer unit will need to be replaced.

3. Drain connection

If the source of the water is the drain connection, this too, can almost always be repaired.  

The drain will either be connected with a flanged elbow or a flanged straight tailpiece.  In either case the leak can be caused by a cracked flange on either piece, a bad gasket, a loose clamp or a cracked housing.  If the tailpiece is bad it must be replaced.  

We always change the gasket when this is the case since it is inexpensive and removal of the old tailpiece can damage it.  If it’s the gasket, those can be obtained at the local hardware store.  They are all the same.  

The tailpiece and gasket are held in place by a circular piece of steel with a protrusion on one end.  The protrusion fits into a slot in the disposer body and a screw fastens the other side into the disposer body compressing the gasket while acting as a retainer over the flange.  

Of course, if the clamp is just loose, tightening the bolt should stop the leak.  Be sure to check for the cause of the loose bolt so that it doesn’t happen again.  If the housing for the clamp is cracked and leaking, the disposer must be replaced.

4. Disposer seals

If the disposer shaft seals are determined to be the source of the leak then the disposer must be replaced.  

All disposers we know of are sealed units and cannot be field repaired.

5. Motor Housing

A cracked motor housing is a very rare occurrence but unfortunately, when this does occur, the entire disposal must be replaced.  

This is also a dangerous situation as water and electricity definitely don’t mix.

Easiest fix of all

Call Yes! Plumbing anytime for help if your garbage disposal is leaking. Operators are standing by to serve you 24/7.

If you think your garbage disposal is not leaking but you think it’s broken, read our guide on simple fixes for a broken garbage disposal.