Few things are more frustrating than a kitchen sink that won’t drain properly. Whether you’re washing dishes or rinsing vegetables, a backed-up sink can bring your routine to a sudden halt—and the smell isn’t great either. If your sink seems to be clogging up frequently, it’s a sign that there may be a bigger issue below the surface. Here’s what might be causing the problem—and what you can do to fix it.
Common Reasons Your Kitchen Sink Keeps Backing Up
Grease Buildup
Grease is one of the top culprits behind kitchen sink blockages. When hot grease is poured down the drain, it may go in as a liquid, but it quickly cools and hardens inside the pipes, creating a sticky buildup that traps food particles and debris.
Even if you rinse with hot water or follow it with soap, grease still clings to the inside of your pipes over time, narrowing the passage and slowing the flow. Eventually, it can lead to a full blockage.
Food Scraps and Debris
Food scraps—especially fibrous or starchy items like potato peels, pasta, and rice—don’t break down easily and can cause serious clogs. If you’re not using a garbage disposal (or using it improperly), food waste can accumulate in the drain and cause backups.
Even if you have a disposal, remember: it’s not a catch-all. Avoid putting eggshells, coffee grounds, or stringy vegetables down the drain.
Soap Scum and Detergent Residue
Over time, the combination of soap, detergent, and water minerals can leave behind a thick residue that coats your pipes. This scum builds up gradually and can contribute to slow drainage or full clogs, especially when combined with grease or food particles.
Clogged or Improperly Vented Drain Line
If your drain line is clogged further down the system—or if your plumbing vent is blocked—your sink may gurgle or drain slowly. Vents allow air into the system to help water flow properly. If they’re blocked (by debris, a bird’s nest, or snow), it can create negative pressure that disrupts drainage.
Damaged or Sagging Pipes
In some cases, older or poorly installed plumbing may begin to sag or deteriorate, especially under the weight of built-up debris. Low spots in the pipe can collect water and waste, making it more difficult for water to flow and increasing the chance of blockages.
How to Fix a Backed-Up Kitchen Sink
1. Start with Hot Water and Dish Soap
If the clog is caused by grease, running hot water and a generous amount of dish soap might help loosen the buildup. Let it sit for a few minutes, then try flushing the drain again.
This method works best for early-stage blockages but isn’t a guaranteed fix for more serious clogs.
2. Try a Plunger or Drain Snake
For more stubborn clogs, a plunger can help dislodge blockages near the drain. If that doesn’t work, a drain snake (also called an auger) can be fed down the pipe to break up clogs further down the line.
3. Check the P-Trap
The P-trap (the curved pipe under your sink) can collect debris and cause backups. You can place a bucket underneath, unscrew the trap, and clean out any gunk that may be lodged inside. If you’re unsure how to do this safely, it’s best to call a plumber.
4. Call a Professional for a Thorough Inspection
If clogs keep coming back or you suspect a deeper issue, it’s time to call in the pros. A licensed plumber can inspect your drain line, clear out any blockages with professional-grade equipment, and check for venting issues or pipe damage that might be contributing to the problem.
Keep Your Sink—and Your Home—Running Smoothly
At Michael Runk Plumbing and Heating, we understand how disruptive a clogged sink can be. Whether it’s a quick fix or a deeper plumbing issue, we’re here to help you find a lasting solution. If your kitchen sink keeps backing up, don’t wait for it to turn into a bigger mess. Contact Michael Runk today for fast, reliable service and expert advice.