How to Fix a Slow-Draining Sink
Updated September 18, 2026
Can I do this myself?
Safe to DIY
Yes, clearing a slow sink drain is a safe DIY job with basic tools. Skip chemical drain cleaners, and call a plumber if several drains back up at once or dirty water comes up in other fixtures.
A sink that takes minutes to empty is usually telling you something is building up in the drain, not that anything is broken. In bathroom sinks the culprit is almost always hair and soap scum wrapped around the pop-up stopper. In kitchen sinks it is grease, food scraps and coffee grounds that stick to the pipe walls and trap everything that follows.
The good news is that most slow drains can be cleared in under an hour with a screwdriver, a plunger and a cheap plastic drain cleaning tool or small drain snake. Work from the simplest fix to the most involved: clean the stopper first, then flush and plunge, then snake the drain. Most clogs never get past step one.
Avoid chemical drain openers. They often only burn a small hole through a clog, they can damage older metal pipes and seals, and they leave a hazardous liquid sitting in the pipe if the clog does not clear, which is exactly when you need to take the trap apart.
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Signs of the problem
- Water pools in the basin and takes a long time to drain
- Gurgling sounds from the drain as water goes down
- A musty or rotten smell coming from the sink drain
- Visible hair or grime around the stopper
- Kitchen sink drains slowly, especially after washing greasy dishes
Common causes
Hair and soap scum on the pop-up stopper
Most commonBathroom sink stoppers sit right in the drain path. Hair wraps around the stopper and its pivot rod, and soap scum glues it together into a thick mat. This is the most common reason a bathroom sink drains slowly.
Grease and food build-up
Most commonIn kitchen sinks, cooking fat and oil cool and harden inside the pipes. Food particles and coffee grounds stick to the fat, gradually narrowing the pipe until water barely gets through.
Debris in the P-trap
SometimesThe curved pipe under the sink (the P-trap) holds water to block sewer gas. Heavier debris, such as small objects, jewellery or sand, settles there and slows the flow.
Blocked vent pipe
Less commonDrains need air to flow freely. If the vent pipe (usually exiting through the roof) is blocked by leaves or a nest, sinks drain slowly and gurgle even when the pipe itself is clear.
Clog further down the branch or main line
Less commonIf other fixtures in the house also drain slowly, or water appears in a nearby tub when the sink runs, the blockage is deeper in the shared drain line and needs a longer auger or a plumber.
Safety first: before you start
- Critical:Do not use chemical drain cleaners, and never combine them with each other or with vinegar, bleach or ammonia. Mixing can release toxic gas or cause violent spattering.
- Critical:If a chemical cleaner is already in the drain, do not plunge, snake or open the pipe. Flush with plenty of cold water if it will drain, ventilate, and warn anyone working on it.
- Wear rubber gloves and safety glasses when plunging or pulling out gunk. Drain water can splash.
- Do not pour boiling water into a sink with plastic (PVC) drain pipes or a porcelain or ceramic basin. Use hot tap water instead to avoid softening joints or cracking the basin.
- Clear the cabinet under the sink and keep a bucket ready before disconnecting anything.
Tools & materials
Tools
- Rubber gloves and safety glasses
- Flashlight
- Adjustable pliers
- Cup plunger (flat-bottomed, for sinks)
- Plastic barbed drain cleaning tool (zip tool) or small hand drain snake
- Bucket and old towels
- Old toothbrush
Materials
- Baking soda
- White vinegar
- Dish soap
- Replacement pop-up stopper, if the old one is broken
Step-by-step fix
- 1
Remove and clean the pop-up stopper (bathroom sink)
Look under the sink behind the drain pipe for a horizontal pivot rod held by a nut. Put a bucket under it, unscrew the nut counter-clockwise with your fingers or pliers, and pull the rod out a few centimetres. Now lift the stopper straight out from the top. Pull off the hair and gunk, scrub the stopper with an old toothbrush, and reinsert the rod through the hole in the stopper's tail when you put it back. Hand-tighten the nut.
Tip: Some stoppers simply lift out, or twist a quarter turn to release. Try that before going under the sink.
- 2
Fish out hair with a zip tool
With the stopper out, push a plastic barbed drain cleaning tool down the drain as far as it goes, twist it slightly, and pull it straight up. Repeat until it comes out clean. This often fixes a slow bathroom sink on its own.
- 3
Flush with hot water
Run the hottest tap water for two to three minutes to rinse loosened debris and soften soap scum. For a greasy kitchen drain, add a good squirt of dish soap first. Only pour boiling water directly into the drain if you have metal pipes and a basin that can take it (stainless steel), and never into porcelain or with PVC pipes.
- 4
Try baking soda and vinegar for mild build-up
Pour about half a cup of baking soda into the drain, followed by a cup of white vinegar, and cover the drain with a plug for 15 to 30 minutes. Then flush with hot tap water. This helps loosen light grime and odours but will not dissolve a solid hair clog. Never use it after a chemical drain cleaner.
- 5
Plunge the sink
Stuff a wet rag into the overflow hole (the small opening near the top of the basin) so the plunger does not just push air out of it. In a double kitchen sink, plug the other drain. Fill the sink with a few centimetres (an inch or two) of water, seal a flat cup plunger over the drain, and plunge firmly 10 to 15 times, then pull off quickly.
- 6
Clean the P-trap
If it is still slow, put a bucket under the curved trap. Unscrew the two slip nuts by hand or with pliers (counter-clockwise), lower the trap and empty it. Clean it out with a brush, check the washers, then refit and hand-tighten the nuts plus a quarter turn.
Warning: Plastic slip nuts crack if over-tightened with pliers. Snug them by hand first and only add a little extra if it drips.
- 7
Snake the drain
With the trap off, feed a small hand drain snake into the pipe going into the wall. Push it in until you meet resistance, tighten the lock screw, and turn the handle clockwise while pushing gently. When it moves freely, pull the cable back out slowly, wiping debris off with a rag. Refit the trap.
- 8
Run water and check for leaks
Run water for a few minutes. Watch how fast the basin drains, and feel around the slip nuts and pivot nut underneath for any drips with a dry tissue.
Stuck on a step?
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How to check it's fixed
- A full basin drains in a few seconds without gurgling
- No drips around the trap slip nuts or the pop-up pivot nut
- The stopper opens and closes properly with the lift rod
When to stop and call a professional
- More than one drain in the house is slow or blocked at the same time
- Dirty water or sewage comes up in a tub, shower or floor drain when the sink is used
- The snake hits a blockage it cannot get through, deep in the wall
- Pipes under the sink are corroded, cracked or leaking at the wall
- A chemical drain cleaner has been used and the sink still will not drain
How to prevent it
- Fit a drain strainer or hair catcher and empty it regularly.
- Never pour cooking fat, oil or grease down the kitchen sink. Wipe pans with a paper towel and bin it.
- Once a month, remove and rinse the bathroom stopper.
- Run hot tap water for a minute after using the sink for greasy or soapy jobs.
Frequently asked questions
Does baking soda and vinegar really unclog a drain?
It helps with light build-up and odours, and it is safe for pipes. It will not break through a solid clog of hair or grease. For those, remove the stopper and use a zip tool, plunger or drain snake.
Can I pour boiling water down the sink?
Only into a metal sink with metal pipes. Boiling water can soften or loosen plastic (PVC) pipe joints and can crack porcelain or ceramic basins. Very hot tap water is safer and works for most grease.
Why shouldn't I use chemical drain cleaners?
They can damage older pipes and seals, they often only clear part of the clog, and they leave a caustic liquid in the pipe that can burn you if you then plunge or open the trap. Mechanical methods are safer and usually more effective.
Why does my sink gurgle when it drains?
Gurgling usually means air is being pulled through a partial clog or the drain is poorly vented. Clearing the stopper and trap often fixes it. If it continues with a clear drain, the vent pipe may be blocked, which is a job for a plumber.
How do I remove a bathroom sink stopper?
Try lifting or twisting it first. If it will not come out, go under the sink, unscrew the pivot nut on the back of the drain pipe, pull the pivot rod out slightly, and lift the stopper out from above.
This guide is general information, not professional advice. Homes differ, so follow your product manuals and local codes. If anything looks different from what's described, or you feel unsure, stop and call a qualified professional. In an emergency, leave the area and call your local emergency number.
Related guides
Leak under sink (P-trap)
Safe to DIYYes, a leaking P-trap is one of the easiest plumbing repairs. It is a low-pressure drain part, so there is no need to shut off the water, just stop using the sink. Call a pro if the leak comes from the wall pipe or the cabinet floor is rotting.
Clogged bathtub drain
Safe to DIYYes, clearing a bathtub drain is a safe and common DIY repair. The main risks are slipping in a wet tub and chemical burns if drain cleaners have been used, so skip the chemicals and work carefully.
Jammed garbage disposal
DIY with precautionsYes, most jams are a safe DIY fix if the disposal is unplugged or its circuit is switched off first and you never put your hand inside. The risks are serious hand injury and electric shock, both avoidable.
Sewer smell
DIY with precautionsMost sewer smells come from dry traps or dirty drains and are safe to fix yourself. If the smell is strong, persistent or you feel headaches or dizziness, ventilate, leave and call a plumber. Roof vent work is for a pro.
Clogged toilet
Safe to DIYYes, most toilet clogs are safe to clear yourself with a flange plunger or a toilet auger. Stop and call a plumber if sewage is coming up in other drains, or if water is spreading toward outlets or through the floor.