7 Common Reasons You Have a Clogged Kitchen Sink

C.E. Larusso
Written by C.E. Larusso
Updated September 15, 2021
A luxurious kitchen sink in front of a window
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Sorry, your garbage disposal is not invincible

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Homeowners spend a lot of time at their kitchen sink; some studies say it can range from 30 minutes to two hours every day. So when it gets clogged, it’s no small problem. Here are seven common culprits behind that clogged kitchen sink and an action plan to fix the problem so you can get right back to that mounting pile of dishes.

1. Fat, Oil, or Grease

Any cooking ingredient with a high amount of fat in it—such as oil, bacon grease, or lard—may have been a liquid when you poured it down the sink, but over time, the fat hardens up as it meets the cool interior of the drain, causing annoying clogs. You should dump any kind of grease into an old coffee can and then get rid of it in the garbage.

2. Starches

Pasta, potatoes, beans, and rice are four common culprits of clogged kitchen sinks. As they expand when exposed to water, they create a paste-like substance that’s an enemy to your pipes. Dispose of these foods in the trash can.

3. Coffee Grounds

Coffee spilled in a kitchen sink
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Similar to the starches we listed above, coffee grounds get heavy when mixed with water, blocking the pipes. Coffee should be thrown away in the garbage, tossed into the compost heap, or sprinkled on the soil of acid-loving plants like roses, as it lowers the soil’s pH.

4. Other Food Scraps

Food should always go into the garbage disposal, the trash, or the compost because over time, bits and pieces of your dinner can become trapped in the P-trap, that curved pipe under the sink. Celery and other stringy foods should never go into the disposal, as they can get wrapped around the blades. Bones, fruit pits, and eggshells are other no-nos; they’re way too hard.

5. Soap Scum

Many soaps are made with fats, and when they are mixed with hard minerals found in some water, they can build up a nasty clog in your pipes. To fix this, hire a local plumber to pressure-clean the pipes and look for soap-free cleansers.

6. Toys and Other Small Objects

If you’ve got kids, there’s a chance that a marble, figurine, or other small object has accidentally been tossed into the kitchen sink, causing the clog. To clear the pipes of any miniature race cars or dinosaurs, you’ll likely want to call in a plumber as you’d need to remove the P- or J-trap.

7. Tree Roots

If you’ve got multiple clogged drains, there’s a chance that your sewer line is backed up, and it could be from tree roots. The roots will look for even the smallest of cracks in your sewer line—which could exist if the lines are older—and will weasel in and grow inside. A plumber will need to break up the tree root and then use a tool to clear the sewer line, and you’ll likely need to get the lines repaired.

What Should I Do If My Drain is Clogged?

A plumber unclogging a kitchen sink using a plunger
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Check the Garbage Disposal

If you suspect the problem might be last night’s ratatouille, you can check the garbage disposal. First try running it to grind up any food scraps, and if that doesn’t work, reset the circuit breaker in case the clog overloaded the motor.

Get Out the Trusty Plunger

There’s a reason the plunger has been around so long and is in nearly every person’s home—it’s a simple, effective tool. Fill your sink with three or four inches of water, then plunge over the clogged drain for 30 seconds or so. Take a break and check the water to see if it is swirling, an indication that it is starting to drain. If not, try plunging again.

Clear the Trap

The trap is that U-shaped part of your sink’s pipe. Given its shape, it's a magnet for clogs. Loosen the fasteners holding the trap on, and make sure to place a bucket below the sink to catch water. Once it’s off, take a look inside to check for anything stuck in it. You can use a coat hanger to push any mass out of it before screwing it back in place.

Snake It Out

Also known as a plumber’s auger, a snake is an inexpensive tool (roughly $30-$50) that, via manual crank, sends a tough line of wire into the pipes to clear out any clogs. You may have to use it several times before the blockage is pushed out.  

Call a Professional

If the simple solutions above don’t work or you have several clogged sinks, this clog might be out of your league. Rather than renting more elaborate equipment and risking the possibility that you make things worse and break or damage your pipes, call a professional plumbing company to be sure that you get the job done right the first time. That will save yourself time and a big headache.

Kitchen Sink Maintenance

To avoid clogs and other problems, you should maintain a clean kitchen sink and follow a regular maintenance routine. These tasks include:

  • Running water while the disposal is on to ensure food scraps get properly flushed away

  • Keeping the amount of food your disposal has to work through to a minimum, so the motor is never overloaded

  • Cleaning the disposal regularly

  • Every week, clear out pipe build-up by pouring half a cup each of baking soda and white vinegar down the drain

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