What Not to Put Down Your Disposal – According to a Licensed Plumber

I want to start off by clearly stating– this list may not match what the manufacturer of your disposal says is safe to put down your disposal. For example, Insinkerator brand disposals state that you can put “uneaten fast food” down your disposal (seriously, the fact that they had to put “uneaten” on there scares me); while we also advise against the urge of putting uneaten fast food down your disposal, we’re going to let you know exactly why certain foods, like fast food, are a big no-nos for your drain. 

 

Consider More than Your Disposal

Your disposal, even with 1/3 horsepower, can handle a lot of food debris. Something not always considered, however, is the condition of your drain line after your disposal. Most kitchen stoppages occur beyond the disposal, known as the disposal tee or p-trap, or sometimes even the drain section in the wall. Your kitchen sink line is 1½” diameter pipe, pretty small when you think about it,  about the diameter of a large barrel curling iron (I know, chick reference, but I am a chick). We expect a lot of that small pipe when we’re putting things down the disposal and what is often the cause of stoppages is a kitchen sink line that has been reduced in diameter due to buildup of food and grease in the line– that 1½” diameter is now down to less than half of its original size. Now, we’re working with a line that is roughly  ¾” diameter on the inside and coated with sticky debris, expecting it to continually handle what we throw down… and this is where bad things happen. Keep in mind that there are even some fittings that are restrictive by design! 

 

Not All Disposals are Created Equally

Disposals come with several different options including horsepower and single grind vs double or even triple grind.  Not all disposals are created equal, so you can’t assume that the 1/3 horsepower special from the hardware store will hold up the same as the 1½ horsepower triple grind version.  We want to guide you through being proactive with your disposal and to use it safely no matter how many horsepower it may have or how many grind levels it may possess.

 

How to Use Your Disposal

This may seem redundant and simple, but have you ever learned the proper steps for using your disposal?

  1. Always use your disposal with the cold water running the entire time
  2. Turn the disposal “on”– you will want to make sure that your disposal is running before you put food waste down
  3. Cramming food down your disposal can cause the disposal to jam; the best practice when putting food scraps down your disposal is to send them down in small portions
  4. Once the food waste has been processed, turn the disposal “off” while allowing the cold water to run for a few more seconds to ensure that all of the debris has been properly flushed from the disposal; the water is able to carry the food waste past the disposal tee and through the p-trap under your kitchen sink

 

What Not to Put Down Your Disposal 

The following list contains examples of foods not to put down your drain; these items are not necessarily bad for your disposal, but, in our experience, they commonly cause stoppages in kitchen sinks.

  1. Coffee grounds – Coffee grounds are sedimentary in nature and can quickly buildup in your kitchen drain line causing a stoppage. Looking for an alternative way to reuse those grounds? A great use for these remains is in gardens as a soil or compost additive. If you’re not a gardener yourself, ask your family and friends if they could use them, or check the several gardening Facebook groups online.
  2. Egg shells – There is a common myth that eggshells are great to put down your disposal because the edges of the eggshells will sharpen the blades inside your disposal– this isn’t true. Your disposal doesn’t have any blades and eggshells, like coffee grounds, are sedimentary and will build up in your drain line creating a stoppage. However, eggshells are also great for composts in gardens, so if you can recycle them do so! Otherwise, eggshells are best sent to your trashcan rather than down your disposal.
  3. Pasta – Whether the pasta is wet or dry, you will want to avoid sending it down your disposal. Pasta can create a stoppage as a result of continued absorption of water while in your drain line.
  4. Rice – Just like pasta, rice will continue to absorb water while sitting in your drain line. Rice is better handled by being thrown away than sent down your drain system.
  5. Beans – You’re probably catching on, foods that expand with water shouldn’t be sent down your drain system; they should be sent safely to your trashcan. Even worse, if these soft, water absorbing foods aren’t sent down your line with enough water, then they can sit in your line and harden again – creating a concrete like stoppage in your line. Do your family a favor and throw pasta, rice and beans away rather than down your sink.
  6. Fibrous vegetables, like celery – Fibrous, stringy vegetables are often the culprit of kitchen sink stoppages– this seems especially true on Thanksgiving. Usually, too much of the product is being sent down the disposal at once for the disposal to properly break down all of the stringy bits. These stringy bits can also catch on the teeth inside of your disposal and create an awful smell in your sink.
  7. Grease or greasy foods– Like uneaten fast food (I couldn’t resist) grease should never go down your kitchen line, ever. Grease is one of the leading causes of kitchen stoppages and, even in small amounts, can build up on the inside of your pipe reducing the diameter drastically and creating a sticky surface for everything to stick too.