The 12 Worst Things to Put Down a Garbage Disposal, According to Plumbers
Garbage disposals are made for small food scraps, not for everything. Putting the wrong items down the drain can clog pipes, jam blades, or damage the unit. We asked professional plumbers to name the most common culprits.
1. Eggshells
Contrary to popular belief, eggshells don’t sharpen garbage disposal blades. “Eggshells, often believed to be disposal-friendly, can surprise you by forming granules that stick to grease, compounding the clog issue,” says Al Fagundes, Master Plumber at A. Fagundes Plumbing and Heating.
Unless you’re interested in a slow buildup of eggshells that eventually cause a clog, start tossing those empty shells in the garbage or compost bin.
2. Starchy Foods
While most people know that flushing grease down the drain is a big no-no, not all realize the damage that starchy foods can do. According to Roy Barnes of Service Force Plumbing, the day after Thanksgiving is one of the busiest days for plumbers due to people clogging their drains with potato peels and starchy leftovers.
“Your garbage disposal will do a great job of grinding starches up into a sticky paste – the finer it grinds, the stickier the mess,” he says. To play it safe and prevent clogs, don’t put potatoes, potato peels, or pasta down your disposal.
3. Grease, Oil, or Animal Fats
All types of grease, including oil and animal fats (like bacon lard), can clog drains. Never place these in the garbage disposal or dump them down the drain. “Pouring grease down the drain may seem like a good idea when it’s a liquid, but as it cools, it will harden, causing clogging,” advises Chris Palmer of Raptor Rooter & Plumbing.
Even if the grease doesn’t cause an immediate clog, some of it will cling to the insides of the pipes, and then other bits of food will attach, slowly building up until the drains are impassable.
4. Fibrous Vegetables
Fibrous vegetables are great for the body but not so good for the garbage disposal. Jimmy Hiller of Happy Hiller, a multistate company that does plumbing and HVAC work, tells us, “Avoid fibrous or stringy foods such as celery, corn husks, onion skins, and artichokes. These can tangle the blades of the garbage disposal and cause it to jam.”
Toss your leftover veggies in the compost bin or trash to keep your blades sharp and jam-free.
5. Coffee Grounds
One of the most controversial items you shouldn’t put down the drain is coffee grounds. Although some TikTokers claim that adding coffee grounds removes bad smells and sharpens garbage disposal blades, you can’t always believe what you see on social media. According to the master plumbers we’ve interviewed, this couldn’t be farther from the truth.
Dumping some coffee grounds may make your sink smell better, but it also creates a sludgy paste that sticks to the drains, eventually causing backups.
6. Bones
Bones are too hard for garbage disposal blades. They’ll either jam the unit or spin around without breaking down, leading to motor strain.
7. Fruit Pits and Seeds
Avocado pits, peach stones, and cherry seeds are too solid. Like bones, they don’t grind and can crack or wear down the disposal over time.
8. Shells (Seafood)
Shrimp shells, lobster shells, or crab shells are tough and fibrous. They tangle the blades and create stubborn blockages.
9. Flour and Dough
When mixed with water, flour, dough, and batter form a paste that sticks to pipes and traps other debris. Over time, this leads to clogs.
10. Paper Towels or Napkins
These items don’t break down in water like food. If tossed into the disposal, they expand, block drains, and damage the grinding mechanism.
11. Rice
Like pasta, rice expands in water and becomes sticky. It can clump inside the disposal or farther down the pipe, forming soft blockages.
12. Medication
Crushing or flushing old pills in the sink is bad for both plumbing and the environment. They pass through water systems and harm ecosystems.
What Can You Put Down a Garbage Disposal?
Save your garbage disposal for the little bits of food that come off your plate as you rinse. Throw everything else in the trash or compost bin. Doing this will help prevent a costly (and inconvenient) plumbing emergency.