How to prevent a plumbing disaster with your garbage disposal

How to prevent a plumbing disaster with your garbage disposal

Garbage Disposal Problems

  I’ve been a master plumber for a long time and have a love-hate relationship with garbage disposals. They’re handy machines if you don’t like to throw food scraps away, but they can cause problems on plumbing drain systems when used improperly.

You must add a significant volume of clear water immediately after dumping the material into the disposal. The clear water is needed to transport the kitchen material to the end of the pipe.


Eggshells and celery are two of the worst things you can put down a kitchen disposal. The eggshells resemble the small rocks and sand I described above. Celery has tough fiber strands that can get wrapped around the moving parts of the disposal. I’d never put either of these food scraps down a disposal.


It’s very important to understand that the inside of many kitchen drain lines is by no means smooth and wide open. The insides of old galvanized iron drainpipes develop a scale over the years. A steel pipe that originally had an inside diameter of 1½ inches might have an inner diameter of only a half-inch or three-quarters of an inch after years of use. I’ve seen these horizontal and vertical pipes completely choked off with deposits.

Modern plastic PVC or ABS plastic pipes can also have deposits, especially hardened grease, clog them. Expecting a slurry of ground-up food scraps to flow like water through partially clogged drain lines is akin to expecting three people to pass smoothly through a conventional doorway at the same time.

The best way to use a garbage disposal is to add the food scraps you wish to grind up and then place the stopper at the top of the opening so you can fill the sink halfway with water. Once you have added the water, pull the stopper out and immediately turn on the disposal.