Top 14+ Things You Thought Were Safe to Toss Down the Sink—They're Not

Your Sink Isn't a Magical Vanishing Portal

Picture this: You're standing at your kitchen sink, scraping leftover spaghetti into the depths below, thinking it'll just disappear forever. Spoiler alert—it won't.

Your sink is basically the highway to your home's plumbing system, and every single thing you send down there is about to take a very expensive detour through your pipes. It's not until we find ourselves dealing with a clogged kitchen sink that all the bits we thought were harmless now come back to bite us.

The drainage system is a delicate and pivotal part of our home's greater plumbing system, and without it, we'd be lost. What seems like harmless disposal today could turn into a $500 plumber visit tomorrow.

Coffee Grounds Create Underground Cement

Like cooking oil, disposing of coffee grounds down the sink might seem harmless, but it's one of the worst offenders for causing blocked drains. Simply put, coffee grounds don't break down in water.

Instead, they clump together, forming a thick, sludgy paste that sticks to the inside of your pipes. And when coffee grounds bind with grease or soap scum, they form stubborn blockages that are hard to clear.

Coffee grounds build up in your pipes and cause blockages. Plumbers say they are the most common cause of drain problems.

Instead of creating this underground disaster, toss them in your compost bin or sprinkle them in your garden—your plants will thank you.

Cooking Oil Turns Into Pipe Glue

Under no circumstances should you ever pour cooking oils down a drain, whether they're cool, hot, solidified or other. Pouring hot oil down a kitchen drain will eventually lead to pipe damage.

Pouring cool oil down your drain can cause it to solidify and result in a clogged pipe. Think of it this way: that bacon grease might be liquid when it hits your sink, but it's about to become the world's most expensive sculpture inside your pipes.

It mixes with any debris, creating congealed, greasy sludge that quickly clogs drains – especially because oil is water-resistant. Greases, fats, butter and margarine are no-gos for the same reason.

Let it cool in a jar, then toss it in the trash like a civilized human being.

Pasta and Rice Become Pipe Monsters

Pasta and rice in particular are things you should never dispose of down a kitchen drain. They absorb liquid and begin to swell in your drains, forming a sticky matter that blocks your drainage system.

Once you put pasta down the drain, it continues to absorb liquid and swell, taking up more space than you could have predicted. The cause of the swelling is semolina, a flour made from durum wheat.

Imagine a single grain of rice expanding like a tiny sponge, then multiply that by every grain you've ever rinsed down the drain. That's your future plumbing nightmare right there.

Flour Creates Homemade Pipe Cement

Flour and starchy foods will also turn into a sticky mess when you wash them down the sink. The mixture of flour and water forms a thick glue-like paste that clings to pipes, trapping other debris and causing stubborn blockages.

There's a reason why mixing batter for a cake is hard on your arms: flour mixed with water creates a thick and glue-like slurry. Imagine that same mix down your drains - little wonder then that it can cause blockages.

Every time you dust flour off your hands over the sink, you're basically creating homemade concrete in your pipes. Use a towel instead.

Eggshells Turn Into Sandpaper

Eggshells are another natural food material that might seem safe to dispose of down the sink but can cause major plumbing dilemmas. Crushed tiny eggshell fragments don't wash away easily.

Instead, they mix with grease and soap scum forming a gritty sandpaper-like paste that clings to pipe walls. Over time this buildup can restrict water flow and cause stubborn blockages.

You might think that a crushed up eggshell will go down the drain smoothly, but it actually is causing a blockage. The sharp, hard edges of the shell will collect other things coming down your drain and eventually cause a clog.

Those seemingly innocent shells are basically building tiny dams in your plumbing system.

Produce Stickers Become Pipe Decorations

Also natural is peeling off the little produce sticker while you're at the sink and letting it wash down the kitchen drain. Well, if you want to avoid a blocked drain, maybe consider not doing that any more.

Over time, those little stickers from your produce build up in your kitchen pipes, and likely leave you with a drain blockage. Many times people wash their fruit and forget to take the sticker off; it falls in the sink and you eventually just let it go down the drain.

Peel them off before you wash your fruit and dispose of it properly. Those little stickers don't dissolve in water and can clog your pipes and block screens and filters or pumps at the water treatment plant.

These tiny plastic squares are basically confetti for your pipes—and nobody wants that party.

Paint Becomes Toxic Pipe Art

Similar to cleaning products, paint should never be poured down the drain even though it's a liquid. It has the potential to pollute the environment and cause your drain to clog.

Many towns have hazardous waste facilities where you can safely dispose of your old or unused paint. Paint can release toxins and harmful chemicals into our water supply if poured down the drain.

Whether oil- or water-based, paint contains many toxins and chemicals that should not end up in our water supply. That leftover wall paint isn't just going to magically disappear—it's going to stick to your pipes and create a very expensive art project you'll never see.

Nail Polish and Remover Melt Your Pipes

No, you shouldn't pour acetone down the drain - and for very good reason. As acetone is highly flammable, it could potentially ignite and cause an explosion.

It can also damage plastic plumbing and contaminate drinking water and the environment. Although it's used to manufacture certain plastics, acetone can actually cause serious damage to PVC plastic pipes.

This is one of the main reasons why you should never pour acetone down the sink or use it to unclog a blocked drain. If your drain pipes are made of PVC (polyvinyl chloride) or at least have PVC junctions, there's a risk the acetone will melt and deform the pipes.

That bottle of nail polish remover isn't just removing polish—it could be removing chunks of your plumbing system.

Cotton Swabs Create Pipe Roadblocks

Cotton swabs and Q-tips are commonly tossed into the toilet instead of the trash, but this can lead to severe blockages in your system. Q-tips and other cotton materials often get caught in your toilet's trap and move across the grating.

They also can get stuck in the flange of your toilet where it meets the floor, creating a blockage directly under your seat. When Q-tips build up, you're sitting on a ticking time bomb that will lead to paper and waste coming back up and overflowing.

Although cotton balls, rounds, and swabs might seem small enough to flush, they can cause big problems inside your pipes. When flushed, these cotton products do not break down in the water; instead, they tend to build up inside pipelines.

Cotton balls are highly absorbent and can snag on materials in pipes, leading to clogs. Even down the sink, these seemingly harmless cotton products become pipe magnets for every bit of debris floating by.

Dental Floss Becomes Underground Fishing Net

Dental floss seems so small and malleable that you'd believe it could be flushed, but it comes with a big risk. Dental floss's small size and flexibility allow it to get caught up on just about anything or wrap around itself and catch other items in a ball larger than you'd expect.

Sharp bends and pipe burrs are top areas for a clog and dental floss is able to take advantage of each and every one. Other than damaging your pipes, flushing dental floss can also cause environmental damage.

When you flush floss, it essentially turns into a net in your pipes, catching and holding onto debris that passes through. That string you use to clean your teeth is basically setting up a debris collection system in your plumbing.

Medications Contaminate Your Water Supply

If you flush your unused or expired medication or crush it up and pour it down the drain, those chemicals will be leaked back into your drinking water and the environment. Always make sure to dispose of unwanted medication at your local pharmacy or police department, which will have access to medical waste disposal units.

Medications shouldn't block your pipes, but they pose a severe environmental risk when added into water waste. Dissolved medications can cause chemicals to end up in our drinking water, pollute groundwater and soil, and harm livestock and wildlife.

Chemicals in medications and paints can end up polluting natural waterways just like incorrectly disposed litter. That leftover antibiotic isn't just going away—it's potentially cycling back into your water glass.

Hair Builds Underground Rope Systems

Hair doesn't break down in water. Instead, it snarls and joins forces with other debris in your pipes, forming large, stubborn clogs.

Always dispose of hair in the trash. We've all had hair wash down the drain, and if you have lots of people in your household using the same shower, excess hair buildup can clog drains in the tub and shower.

One of the easiest ways to ensure that hair doesn't clog your drains is to require that after each shower or bath, the area is cleaned, and all hair is removed. Wet hair is sticky and, combined with other chemicals, can be hard to remove from a drain if left for too long.

Every strand that goes down your drain is essentially building a rope system designed to catch everything else.

Paper Towels Aren't Toilet Paper's Cousin

The only paper product that should go down your drain is toilet paper. It has been specially designed to break down and disintegrate in water.

Always dispose of other paper products such as paper towels, cotton balls, and feminine hygiene products in the trash. These items are extremely absorbent and will easily clog your pipes.

Paper towels may be super absorbent but they are not designed to break down in water like toilet paper. Just ask the Brawny Man, he'll tell you.

Paper towels+ flushing them down the toilet=clogged toilet. It is very difficult to get paper towels to move down the sewer line after they've been flushed down the toilet.

That "super absorbent" quality you love? It's exactly what makes them pipe destroyers.

The truth is, your sink handles water and specifically designed drain-safe products—period. Everything else is basically an expensive science experiment waiting to happen in your pipes.

Over time, though, it can lead to stubborn blockages, foul smells and even possible pipe damage. Worst still, some substances even pollute waterways and harm the environment.

Knowing what to avoid putting down your sink helps you maintain smooth-flowing drains while keeping avoidable plumbing repairs to a minimum. Your future self (and your bank account) will thank you for treating your plumbing system with the respect it deserves.

What surprised you most on this list?