Plumbing

Slow draining sink? Unclog it without chemicals

A slow sink usually gets worse if you leave it. The clog is often within a foot of the drain opening, close enough for a $5 plastic snake or a plunger to reach, so you won't need drain chemicals. In a bathroom sink it's usually hair and soap scum knotted just below the stopper, which is why pouring things down rarely helps and pulling the stopper often does.

A plastic drain cleaning strip pulling a clump of hair out of a bathroom sink drain, with the pop-up stopper set on the counter
A plastic drain strip pulls out the hair that slows most bathroom sinks.
Quick answerPull the stopper and clean it, then use a plastic drain snake. If that doesn't do it, plunge with the overflow blocked, or take the trap off and clean it.
Worth checking firstIf only one sink is slow, the clog is close, usually right under the stopper. If the tub or toilet gurgles when the sink drains, the problem is further down the line, and a plunger or snake at this sink won't reach it.

Good to knowRenter-friendly

Mike TurnerWritten and reviewed byMike TurnerUpdated Sources and safety notes
Moderate20–45 min$0–15
Under-sink P-trap diagram showing tailpiece, slip nuts, trap and a bucket placed below
The P-trap (4) under your sink holds water and catches most clogs. Put a bucket underneath (5) before loosening the slip nuts (2, 3) by hand.

Where the clog is

In a bathroom sink, the clog is usually hair tangled with soap, just below the stopper. In a kitchen sink, it's more often grease and food that hardened in the curved pipe under the sink, called the . So for a bathroom sink, start at the stopper. For a kitchen sink, the trap is the better bet.

What clogs a sink

Hair and soap

Hair wraps around the stopper and mixes with soap into a rubbery plug a few inches down.

Grease and food

In kitchen sinks, grease cools and hardens in the pipe and catches bits of food.

A full P-trap

The curved pipe under the sink is meant to catch things. Eventually it catches enough to slow the water down.

A blocked vent

If the sink gurgles and drains slowly even when the pipes are clear, the plumbing vent on the roof may be blocked.

Which sink, which clog?
SinkUsual clogBest first try
Bathroom sinkHair on the stopperPull the stopper, then a plastic drain snake.
Kitchen sinkGrease and foodPlunge, then clean the P-trap.
Double kitchen sinkClog past where the two sides joinBlock one side with a wet rag, then plunge the other.
Gurgles and drains slowly, pipes are clearBlocked ventA job for a plumber or roofer.
If you've used drain cleanerIf you've already poured chemical drain cleaner in, don't plunge or open the trap. It can splash. Wear eye protection and gloves, don't add any other product, and if the sink is still full, call a plumber and tell them what you used.

Clear the clog

0 of 5 done
  1. Pull the stopperMost bathroom stoppers lift out, twist out, or come free when you loosen a nut on the rod behind the drain. Sometimes the hair wrapped around it is the whole problem.
    Something went wrong?
    • The stopper won't come out Look under the sink for the nut on the pivot rod behind the drain. Unscrew it, pull the rod back, and the stopper lifts out.
    Bathroom sink stopper lifted out of the drain with a clump of hair wrapped around its post
  2. Use a plastic drain snakePush it down the drain, wiggle it, and pull it straight up slowly. Keep going until it comes up clean, then run hot tap water for a minute.
    Plastic barbed drain snake pushed down a sink drain and pulled back up with hair caught on the barbs
  3. PlungePut a few inches of water in the sink and stuff a wet rag into the overflow hole so the plunger can build pressure. Give it 10 to 15 firm pumps.
    Something went wrong?
    • The plunger just sucks water up and down Plug the overflow hole with a wet rag first, and make sure the plunger cup is fully under water.
    Cup plunger over a sink drain with a wet rag stuffed into the overflow hole
  4. Clean out the trapPut a bucket underneath, loosen both by hand, and drop the trap into the bucket. Rinse it out and put it back, hand-tight plus a quarter turn.
    Something went wrong?
    • The slip nuts won't loosen by hand Use slip-joint pliers wrapped in a rag. Turn counterclockwise as you face the nut.
    • The trap is cracked or the nuts are stripped Take it to the store and buy a matching trap kit. They're inexpensive and come with new nuts and washers.
    P-trap removed from under a sink and held over a bucket after loosening both slip nuts by hand
  5. Check for leaksRun water for a full minute and slide a dry paper towel under each nut. If it comes back damp, snug that nut a little more.
    Something went wrong?
    • A nut still drips after tightening Take it apart and check the washer. If it's flattened or twisted, replace it, and make sure the pipes line up straight before tightening.
    Dry paper towel held under each slip nut while water runs to check for drips

Watch it done

How to Unclog a Sink -- The Right WayBy Home Repair Tutor on YouTube. Their method may vary a little from ours.
Watch on YouTube
How you'll know it's fixed
  • Water drains out of the sink without backing up
  • The snake comes up clean
  • A dry paper towel under each slip nut stays dry after a minute of running water

Still backing up? The clog may be past the trap, inside the wall.

If the water still sits in the sink

If plunging didn't work, check that the overflow hole was blocked with a wet rag. Without that, the plunger just pushes air out the top.

If the kitchen sink backs up into the other basin or the dishwasher, the clog is past the trap, in the pipe inside the wall. A small hand auger fed through the trap arm can reach it.

Keeping it clearOnce a month, pour a kettle of hot, not boiling, water down bathroom drains. It softens soap buildup before it turns into a clog. Shower drains clog with the same hair and soap; here is how to clear a shower drain.
Call a plumber ifSeveral drains backing up at once, or a toilet gurgling when you run the sink. That points to a clog in the main line.Fix it yourself or call? Compare the cost →

What a pro typically charges (a rough estimate; prices vary by area): Clearing a sink clog typically runs $125–$275 from a plumber. Main line clogs cost more, often $200–$500.

Find a plumber near you

If it's a different drain

Sink clog questions

Does baking soda and vinegar clear a clog?

It can freshen a slow drain, but it rarely clears a real clog. A plastic snake is faster and more reliable.

Are chemical drain cleaners bad for pipes?

Occasional use is usually fine for modern plastic pipe, but they can damage older metal pipes, and they make it dangerous to open the trap later.

Why is it still clogged after plunging?

The clog is probably packed hair or grease in the trap. Take the trap off and clean it.

Is boiling water safe for drains?

Hot tap water is fine. Boiling water can soften plastic pipe joints and crack porcelain sinks, so save the kettle for metal pipes.

How do I keep sinks from clogging?

Use a hair catcher in bathroom sinks, wipe grease into the trash instead of the drain, and run hot water for a minute after washing dishes.

Can I use the sink while it's draining slowly?

You can, but keep an eye on it. Grease and food only make it slower, so it's worth clearing before the weekend dishes.

Why won't my bathroom sink drain?

Pull the stopper and clean it, then use a plastic drain snake. If that doesn't do it, plunge with the overflow blocked or clean out the trap.

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GrabTheHammer Team

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We're a small team of writers and editors who check every guide against manufacturer instructions and common code requirements. Our goal is to help you understand the problem, tackle what you safely can and know when to call a pro.

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A helpful next stepBathroom sink stopper not workingAdjust the clevis strap and pivot rod under the sink, clean hair off the stopper, snug a leaking pivot nut, or replace the pop-up drain.