Foods You Can & Can’t Put Down a Garbage Disposal
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The term “garbage disposal” is a bit misleading, considering it’s designed to dispose of food waste exclusively. We trust you’re not running plastic, glass, and metal through your disposal, but there are also some less-than-obvious foods that land on the No list below.
We put garbage disposals to the test in our lab, but we also spoke with disposal manufacturers and experts in plumbing and wastewater treatment to nail down a definitive list of what you can and can't put down the disposal. We also surveyed 1,040 Americans who own and use garbage disposals on what they routinely send down the drain. Judging by the responses, some of the “yes” and “no” foods might surprise you.
Here's a quick reference guide. And for all the details, read on below.
What Foods Can You Put Down Your Garbage Disposal?
YES
NO
Fruit Scraps
Fruit Pits
Vegetable Scraps
Corn Cobs
Cooked Meat
Small Bones
Leftovers
Ice
Clam or Oyster Shells
Grease
Oil
A Large Amount of Vegetable Peels
A Large Number of Eggshells
Corn Husks
Artichokes
Any Non-food Items
Illustrations by Chris Philpot
What Foods Can You Put Down Your Garbage Disposal?
YES
Fruit Scraps
Fruit Pits
Vegetable Scraps
Corn Cobs
Cooked Meat
Small Bones
Leftovers
Ice
NO
Clam or Oyster Shells
Grease
Oil
A Large Amount of Vegetable Peels
A Large Number of Eggshells
Corn Husks
Artichokes
Any Non-food Items
Illustrations by Chris Philpot
Foods You Can’t Put Down the Disposal
For the most part, garbage disposals can grind pretty much anything you throw at 'em. Your plumbing, however, is another story. Turns out, that bacon grease you poured down the drain awhile back could be the beginning of a clog down the road.
Fats, oils, and grease. All our experts agreed that fats, oils, and grease (what the industry refers to as FOGs) should never go into your disposal—or any drain for that matter.
“They might start out in a liquid state but those materials will congeal and eventually cause clogs further downstream in the water system,” says David Duest, director of the Deer Island Treatment Plant in Boston.
In a nationally representative survey, CR asked users what foods they put in their grinders, and an astounding 33 percent of users put grease and fats into their disposals.
“That’s not surprising,” says Rebecca Shelton, a wastewater engineer based in the Atlanta metro area. “Grease is related to about 70 percent of sewer overflows.”
And you may not realize, she adds, that creamy foods like peanut butter or dairy products fall into the FOGs category. So butter, heavy cream, and ice cream are also out of the question.
Sometimes it’s unavoidable for small amounts of grease to go down the disposal—think sautéed vegetables or creamy sauces—which is why you should always use cold water when operating the disposal. “Cold water is key,” says Alyssa Wiegand, product manager at Moen. “It causes small amounts of grease to solidify." Then the disposal can break those solids up, reducing the chances of a clog.
Starchy foods. Scraping dregs of macaroni off a plate is fine, but a takeout container of week-old fried rice? Toss it in the trash. “Large quantities of starchy foods like rice, pasta, and potatoes break down into a mush that can clog your drain and also gum up your disposal,” says Paul Abrams, the public relations director for Roto-Rooter.
Fibrous vegetables and peels. Celery, corn husks, artichokes, edamame pods, asparagus, and rhubarb are also problematic. “Premium garbage disposals with multi-grind technology can handle fibrous foods in small amounts,” says Eric Schultz, director of product management at InSinkErator. “But stringy materials tend to go through most garbage disposals and ball up in your plumbing, causing clogs.”
As counterintuitive as it seems, fruit and vegetable peels can cause similar problems, especially if you cram a bunch into the disposal at once. “Individual peels are very thin and don’t have much heft to them, so they can actually slip through the grates,” Schultz says. “And they can cause clogs in the same way that fibrous vegetables do.”
According to our survey, 59 percent of users are guilty of tossing vegetable peels into their disposals (though we didn’t inquire about the quantity), while 20 percent put in artichokes, and only 4 percent attempt to grind corn husks.
Eggshells, shellfish, and coffee grounds. Eggshells are another common throwaway food that 33 percent of our survey respondents say they put into the garbage disposal.
Seems harmless enough, but they don’t decompose quickly and a large amount of them accumulate and stop up the drain, especially if you’ve got older pipes. The same goes for shellfish and coffee grounds, which don’t break down easily and are also quite oily—a double whammy.
Foods You Can Put Down the Disposal
Basically, all other foods—from peach pits to corn cobs to cooked steak—can be ground up and washed down the drain.
But according to our survey, there are a handful of foods homeowners didn’t realize they can put down the disposal. Only 9 percent of respondents said they put small bones in their disposals. But manufacturers insist it’s perfectly safe.
“People worry that bones will break the disposal’s blades—but food waste grinders actually don’t have blades,” says InSinkErator’s Schultz, explaining that an impeller uses centrifugal force to spin food up against a stationary grind ring. “What you may notice with entry-level disposals is they can be quite loud and vibrate a lot when grinding bones, but they’ll still pulverize them into small particles.”
In CR’s garbage disposal lab, we test each model with heavy-duty beef rib bones to really challenge them, and indeed, they were all able to adequately grind up bones. If you plan to regularly grind bones (nothing larger than a rib bone) and other heavy-duty foods, like fruit pits and corn cobs, opt for a garbage disposal with more horsepower.
“The higher the horsepower, the more difficult foods it can process,” says Moen’s Wiegand. Disposals with 1 hp can tackle bones without rattling the sink or making it feel like your ears are bleeding.
Plumbers are a bit more cautious when it comes to putting bones into the disposal, however, also because it comes down to what your home's pipes can handle.
“Even small and medium-sized chunks of bone and other hard foods potentially increase the odds of a clog in your drainage system,” says Abrams. The risk level depends on the age and condition of your pipes. “Large food debris might not present a problem in a newer home with a network of pristine PVC drain pipes, but clog risks go up substantially if you have rugged old cast-iron drain pipes.”
Best Garbage Disposals From CR's Tests
Below, five impressive garbage disposals from our tests, listed in order of CR rank. See our garbage disposal buying guide for more on how to find the right disposal for your kitchen. And for test results on almost 40 models, check CR's full garbage disposal ratings.
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