11 Worst Things to Put in Your Garbage Disposal

A kitchen sink equipped with a garbage disposal can be wonderfully convenient. However, if not properly maintained, it can become more trouble than convenience. If you're lucky enough to have a garbage disposal that will crush up food waste with the flick of a switch, keep in mind there are items which should never go down your drain. We asked a professional plumber what his plumbing company sees most often causing problems with garbage disposals.

1. Bones

If you flip on your garbage disposal and it makes a terrible racket, it’s likely that an animal bone, shells from shellfish, or something similar has fallen down into the drain. Bones are rich in calcium, making them hard and difficult to break apart. Bones in your garbage disposal will just continuously spin around with the blades, potentially damaging your blades. If they do make it past the garbage disposal blades, they certainly won’t make it down the drain pipes.

2. Grease, Oil, and Fats

After frying up a pan of bacon, it’s tempting to pour that piping hot oil down the kitchen sink. However, although it is a liquid initially, grease and oils solidify as they cool, which will unquestionably accumulate down in your pipes, creating backed up, clogged pipes. It’s an enticing thought to try to cheat by pouring or running hot water down the drain to keep the fats in a liquid state, but once these fats have made it into your drains, there’s no guarantee that hot water will come into contact with the grease enough to liquify it. Rather than grease accumulating in your pipes, best to let cool and then pour that bacon grease in the trash.

3. Vegetable and Fruit Peelings

Such a soft, organic material may seem unproblematic to your garbage disposal. However, fruits and vegetables are full of fiber, especially in their outer peelings. When your disposal blades chop these peels up, it creates a gummy paste. This paste acts much like cholesterol in your waste piping system; it will eventually clog the system and cause backed up pipes. Be particularly mindful of certain types of peelings, which can be an even greater risk to your garbage disposal. Potato peels are full of starch, which will create a much stickier paste ripe for clogging. Onions skins are also a culprit of clogged drains due to the thin membrane underneath the outside dry layer. Rather than risking your draining system by putting your vegetable and fruit peels down the garbage disposal, these organic materials are perfect for composting to create nutrient-rich soil for your plants or gardening. Or just toss them in the garbage bin.

4. Fruit Pits

Vegetable and fruit peelings can cause a problem due to their fibrous makeup, but it’s nothing compared to the fiber found in the pits of certain fruits. Peach pits, cherry pits, nectarine pits – all of these are rich in fiber, making them as hard as wood. Would you put a piece of wood down your garbage disposal? Hopefully not, which is why it’s best to throw those pits in the garbage bin. Large pits aren’t the only culprits you need to watch out for. Even small seeds have that same fibrous strength, so opt to throw that apple core in the trash rather than down the garbage disposal.

5. Egg Shells

While calcium-rich the same way bones are, egg shells are deceptively fragile. It’s easy to think that your garbage disposal will chop those eggshells up and send them on their merry way down the drain. However, while the eggshells will be chopped up into tiny pieces, it’s not enough for those pieces to make their way through your drain. These tiny pieces can accumulate together with the help of the shell’s inner membrane. So, while it seems like your garbage disposal is doing its job by crushing up the eggshells, after a few months, you may rethink putting egg shells down your garbage disposal when you fish out a collective mass of broken egg shells that was clogging your drain.

6. Coffee Grounds

When providing plumbing maintenance services, many plumbers notice coffee grounds settled in the disposal’s base. Because it’s used to make your morning beverage and is so finely ground, it’s not uncommon to think coffee grounds should be a non-issue to your garbage disposal. However, although it’s easy to associate coffee grounds with your delicious hot drink which goes down the disposal easily, coffee beans are actually seeds from coffea plants. As with other seeds and pits, they are rich in fiber, even when finely ground. Adding water to coffee grounds will make them dense, which can potentially cause clogging in your drain. Best to throw that full coffee filter in the garbage bin.

7. Celery and Other Stringy Vegetables

Organic materials that are rich in fiber seem to be the biggest offenders to your garbage disposal and can lead to needing a plumber for a clean out or plumbing repair. Fibrous, stringy vegetables are an even bigger threat. Unlike other vegetable peelings that turn into a sticky paste when put down your garbage disposal, vegetables like celery stalks, asparagus, corn husks, and other fibrous, stringy vegetables can get tangled around the disposal's blade- even burning out the motor of the garbage disposal. But these organic materials are great for composting. Otherwise, nix stringy vegetables by sending them to your trash bin.

8. Pasta and Rice

Soft pasta and rice might appear to be perfectly safe to put down the garbage disposal, as you would expect your disposal blades to chop them up easily and send them down the drain. However, pastas and rice are full of starch, which can easily stick to your drainage pipes. Additionally, both pasta and rice expand when exposed to water. Sticky, expanding starches can accumulate in your drain and will not make for happy drainage piping.

9. Oatmeal

Similar to pasta and rice, the danger of putting oatmeal down the garbage disposal lies in its tendency to expand with water. Because of how small oats are, most of them slip past the disposal blades easily. But once they get wet down inside your drain, the expansion begins, which can lead to clogged pipes.

10. Paper, Plastic, and Glass

Contrary to its name, most people know that actual garbage should not go down the garbage disposal. However, sometimes it can be tempting to throw away small garbage down the disposal – twist ties, cigarette butts, or small pieces of food packaging – thinking that, because it’s so small, how much damage could it really cause? Unlike food items commonly put down the garbage disposal, even the ones that shouldn’t go in the disposal, plastics, paper, and glass are not biodegradable. You can rough it up a bit with the disposal blades, but your trash will never decompose like food will. Don’t let its name fool you, keep garbage out of your garbage disposal.

11. Paint, Plaster, and other Chemicals

Working on home renovations and think your paint or plaster can go down your garbage disposal since it's in liquid form? There are many reasons it can be dangerous to put harsh chemicals down your drain. While liquid initially, paints and plaster will unquestionably harden (quicker than you might think), leading to clogged drains. Additionally, the chemicals that do make it past your drainage system and end up in your local water reservoir can be fatal to the ecosystem that lives there.

Garbage disposals are meant to add convenience to our lives, but if not used properly, they can create a massive headache. Remember, these 11 items that should never be placed into your plumbing system. It is also wise to have a professional plumber take a look at your system if a problem should occur. Often times a quick plumbing clean out can save you money from a more costly plumbing repair or replacement down the road.