Kitchen Sink Won't Drain: 7 Fixes to Try

A kitchen sink won't drain at the worst possible moment — usually right after dinner, with a sink full of dirty dishes and standing water that smells like yesterday's leftovers. Before you panic or pay for a service call, know this: most kitchen sink clogs are caused by grease, food scraps, and soap buildup within a few feet of the sink itself, which means you can usually fix the problem yourself in under an hour. Below are seven fixes ordered from simplest to most involved, so start at the top and work down until the water flows again.

1. Check the Garbage Disposal First

If your kitchen sink won't drain and you have a garbage disposal, start there — it is the most common culprit and the easiest fix. A jammed or tripped disposal blocks the drain opening completely, so water has nowhere to go. First, look under the sink and find the small red reset button on the bottom or side of the disposal unit. Press it firmly. If the disposal hums but doesn't spin, the flywheel is jammed. Turn off the power at the switch, insert an Allen wrench into the hex-shaped opening on the bottom of the unit, and work it back and forth to free the jam. Remove the wrench, restore power, press the reset button again, and run cold water while turning the disposal on. In most cases, the drain clears immediately.

If the disposal runs normally but the sink still drains slowly, the blockage is farther down the line — move on to the next fixes. And if you don't have a disposal at all, skip straight to the P-trap.

To keep the disposal from jamming again, always run cold water before, during, and for 15 seconds after grinding — cold water keeps grease solid so the disposal can chop it and flush it through instead of letting it melt and coat the drain walls. Never put coffee grounds, eggshells, pasta, rice, or fibrous vegetables like celery down the disposal; they either turn to paste or tangle the impellers. And skip the lemon-peel trick as a clog fix — it freshens the smell but does nothing for an actual blockage.

2. Clear the Sink Trap (P-Trap)

The curved P-trap under your sink is designed to hold water and block sewer gases, but that same curve makes it a magnet for grease, coffee grounds, and food particles. When a kitchen sink won't drain, there is a good chance the trap itself is packed solid. The fix is simple and requires only a bucket, a pair of channel-lock pliers, and an old towel.

Place the bucket under the trap, then loosen the two slip nuts on either end of the curved pipe by hand or with the pliers. Pull the trap down and dump its contents into the bucket — expect a foul-smelling sludge of grease and food. Run a bottle brush or old toothbrush through the trap to scrub the inside walls, rinse it thoroughly in another sink or with the garden hose, and reinstall it, hand-tightening the slip nuts (don't overtighten or you'll crack the plastic). Run hot water for a minute to confirm the drain is clear. While the trap is off, take a quick look at the common causes of slow drains so you can spot early warning signs next time.

3. Use a Plunger the Right Way

If the trap is clean but the sink still won't drain, the clog is deeper in the branch line, and a plunger is your next best tool. Use a cup plunger (the simple rubber-cup kind, not the flange style made for toilets). For a double sink, seal the second drain with a wet rag or a sink stopper — without a seal, the pressure escapes out the other side and the plunger does nothing. Fill the clogged side with a few inches of water so the plunger cup is submerged, then plunge with firm, steady strokes for 20 to 30 seconds. The goal is pressure and suction, not speed. Pull the plunger up sharply on the last stroke and watch the water — if it starts swirling down, you've broken through. Run hot water for a minute to flush the loosened debris. If two rounds of plunging change nothing, move on rather than risking damage by plunging endlessly.

4. Try Baking Soda and Hot Water

For grease-based clogs — the most common reason a kitchen sink won't drain — a baking soda flush can dissolve the buildup without harsh chemicals. Pour about half a cup of baking soda directly into the drain, followed by half a cup of white vinegar. Let the fizzing reaction work for 15 minutes; the agitation helps loosen grease clinging to the pipe walls. Then flush with a kettle of near-boiling water (not a rolling boil, which can soften PVC joints — just steaming-hot tap water or a kettle that's cooled for a minute). This method works best on slow drains and partial clogs rather than fully blocked pipes, and it's safe for septic systems. Repeat once if needed, then make this flush a monthly habit even when the drain runs fine. Kitchen drains accumulate a thin layer of grease with every dishwashing session, and a regular baking soda flush dissolves it before it hardens into a real clog. It's the cheapest preventive maintenance in your kitchen — about fifty cents a month — and it keeps you from needing the stronger fixes on this list. Avoid chemical drain cleaners at this stage — they rarely work on kitchen grease clogs and can damage pipes, which is why many plumbers charge extra to handle chemical-treated drains.

5. Snake the Drain Line

A drain snake (also called a drain auger) reaches clogs that plunging and flushing can't. A basic 25-foot hand-cranked snake costs $25 to $40 at any hardware store and handles most kitchen sink clogs, which typically sit within 10 to 15 feet of the sink. Feed the cable into the drain while turning the crank clockwise; when you feel resistance, you've found the clog. Work the cable back and forth through the blockage until the resistance gives way, then retract the cable and flush with hot water. For a full walkthrough, see our guide on how to snake a drain. Wear gloves — what comes back up is never pleasant. If the snake hits a hard stop that won't budge or the cable won't advance more than a few feet, stop and call a professional rather than forcing it; you could damage the pipe or push the clog tighter.

6. Check the Drain Vent

Sometimes the drain line is clear but the sink still won't drain properly because of a venting problem. Every drain needs air behind the water to flow, and that air comes from a vent stack (usually through the roof) or an air admittance valve under the sink. Signs of a vent issue: the drain gurgles, water drains slowly even though snaking found nothing, or the problem comes and goes. Check under the sink for an air admittance valve — a small cap on a vertical pipe. If it's stuck closed or clogged with grease, it can't let air in. You can unscrew it and clean it, or replace it for about $10. If your vent runs through the roof, check that the opening isn't blocked by leaves, a bird nest, or snow. Vent problems are uncommon but worth a five-minute check before you pay for a service call.

7. When to Call a Plumber

Stop DIYing and call a professional if any of these are true: multiple fixtures are backing up at once (the kitchen sink plus the bathroom or tub), which signals a main sewer line clog; water backs up into the sink when you run the dishwasher or washing machine; you've snaked the line and the clog returns within days; or you smell sewage. A main-line clog is not a DIY job — it needs professional equipment like a powered auger or hydro jetting, and attempting it yourself risks flooding your kitchen with sewage. Professional drain cleaning typically runs $150 to $350 for a kitchen branch line; see our breakdown of drain snake costs so you know what to expect. For a stubborn clog that none of these fixes resolve, explore the full drain cleaning guides on this site or get a pro on the job before standing water causes bigger problems.