The Most Surprising Garbage Disposal Dos and Dont’s, According to Plumbers

Garbage disposals are marketed as a must-have for anyone who doesn’t want to stink up the kitchen with smelly food scraps. Just scrape your plate into the sink and let the disposal chew it up and wash it away.

But according to plumbers, that’s not how they’re supposed to be used.

“Most people think they can scrape their plates right into the garbage disposal, but they’re not designed for that,” says Paul Abrams, public relations director at Roto-Rooter. “People abuse them so much. Its name is its biggest enemy.”

Instead, he says, disposals are designed to grind up the leftover bits after you’ve scraped your plate into the compost or trash. Basically, it’s an expensive way to avoid having to touch a dirty sink strainer. “There’s a place for disposals,” he says, “but I wish people would use them the way they’re designed to be used.”

First and foremost that means NOT using the garbage disposal as a literal “garbage disposal,” and never putting grease or fats down it. And, no, running hot water and adding a bunch of dish soap to break it up won’t make it better — it just moves the problem further down the line.

“Cooking greases and fats are a real no-no,” says Abrams. “They turn to goo and they’re the hardest clogs to get rid of. A Roto-Rooter machine spinning around is effective at breaking up objects that cause clogs, but grease is just goo and the machine just moves it around.”

Even if you’ve managed to avoid a clog at home, you’re creating potential problems for your city’s sewer system. “We’ve all heard about these ‘fatbergs’ in England,” he says. “Even if the grease does make it through your home’s pipes, it causes problems we, as a society, all have to pay for.”

Diane Dulken, public information officer for the City of Portland Environmental Services in Oregon, couldn’t agree more. “We recommend people keep food, especially grease, out of the sewer system. That means using garbage disposals less or not at all.”

Clearly the city isn’t a fan of putting food down the drain, no matter how well the disposal can grind it down. That goes for commercial units too.

“We actually have a program that works with restaurants, which are large producers of waste, to prevent clogged sewer pipes,” says Dulken. “Among our top recommendations: Remove disposals and opt for composting.”

What’s the problem with food scraps? “Food scraps require extra treatment at wastewater treatment plants,” says Dulken. “Composting turns waste into a resource, whereas garbage disposals turn waste into a sewer problem waiting to happen.”

So before you upgrade to one of those new extra-powerful garbage disposals that purport to even grind up bones, consider this: They may work, but your city’s sewer department will hate you for it. And unless you have modern, new pipes, you’re asking for a clog. “If you live in a house with old pluming or have a septic, a garbage disposal is not really compatible,” says Abrams.

If you want to be a conscientious citizen and you have a garbage disposal, you’ve got a couple of options: Either put a sink strainer over it and pretend it’s not there, or use it judiciously. Put all the food waste you can into the compost and follow these dos and don’ts to keep it, your home’s pipes, and your city’s sewer system running smoothly.

“All things in moderation,” says Abrams. “Your disposal and pipes can handle a few scraps, but a lot of people say, ‘Oh, I have a bowl of leftovers that’s been in the fridge a while, I’ll just put it down the disposal’ and that’s too much.”

This might come as a surprise, but pasta, rice, potato peels, even mashed potatoes, should not go down the disposal unless it’s just a small amount from rinsing your already-scraped plate. “That starchy stuff turns to goo when it gets down in your drain, then it goes down into the pipe and usually will cause a clog,” says Abrams.

Disposals aren’t made of actual blades, so they’re not going to be able to handle hard things like bones and corn cobs. And stringy things (like celery and rhubarb) will just clog things up. Things will get moved around, Abrams says, but because garbage disposals don’t actually have blades, they don’t do a good job cutting food up. Instead, things will just get twisted and get caught.

“Disposals have metal pulverizers, if you will, but they’re not blades,” says Abrams. “They spin and they’re weighted to one side. There’s a grinder and an outer spinning shredder ring that has sharpened edges on it. They don’t need to be sharpened.”

Your garbage disposal is bound to get a coating of gunk from time to time. And that gunk can interfere with how well the disposal does its job at grinding. It also can make it smelly. Abrams says the best way to clean the disposal is to run it with a cup of ice cubes and some dish soap. “The ice will knock the gunk off. White vinegar is also a good product to use, and some baking soda for foaming action. That’ll add some freshness and do some cleaning as well.” Check your manufacturer’s recommendations, as some models might require different cleaning methods.

Avoid seeds, coffee grounds, eggshells, popcorn kernels, and, of course, bits of glass or plastic. “These things can get between the shredder ring and the wall of the disposal,” Abrams says. “They get caught in there and then it can’t move and trips the breaker. You’ll flip the switch and it’ll buzz and nothing happens.”

Some experts say to run the disposal with hot water, which will liquefy any residual fats and let it flow away. Others swear by cold because it’ll solidify the fats and let it be carried away with the water. “If you have 12 Roto-Rooter plumbers in a room, half would say to use hot and half would say cold — and both explanations have logic to them,” says Abrams. But he says it doesn’t really matter.

Got anything else to add here? Leave your dos and don’ts in the comments below.