How to Unclog a Slow Bathroom Sink Drain

Start With the Simple Fixes

A slow bathroom sink is almost always hair, soap scum, and toothpaste buildup in the stopper or the trap just below it. Work through these fixes from easiest to most involved before reaching for a chemical drain cleaner, which can damage older pipes with repeated use.

How to Unclog a Bathroom Sink: Quick Overview

Learning how to unclog a bathroom sink usually starts with the stopper and P-trap, since that’s where hair and soap scum build up first. Work through the fixes below before reaching for a chemical drain cleaner. Dealing with a kitchen clog instead? Our clogged kitchen sink guide covers that separately. And if slow drains are a recurring problem throughout an older home, it may point to bigger pipe issues covered in our plumbing repipe cost guide.

Tools You’ll Need

A flat-faced plunger, a bucket, an adjustable or open-ended wrench, and a wire clothes hanger. A cheap plastic drain snake from the hardware store makes this easier but isn’t strictly required.

Step-by-Step

Plunge it first. Fill the sink with a couple inches of water, plug the overflow hole with a wet rag so you get suction, and plunge firmly for 20 to 30 seconds. Flush with hot water afterward. If that doesn’t clear it, pull the stopper. Most bathroom sink stoppers unscrew or lift out after loosening the pivot rod nut underneath the sink. Hair and soap scum almost always ball up right at the base of the stopper, and just removing that gunk with a wire hanger solves the problem more often than anything else on this list. Try a natural clean-out next. Pour a half cup of baking soda down the drain, follow with a half cup of vinegar, let it fizz for about an hour, then flush with hot water. If it’s still slow, snake it. Feed a drain snake into the pipe, turn the handle clockwise as you push to catch debris, then pull it back out slowly. As a last resort, clean the P-trap. Put a bucket under the curved pipe below the sink, loosen the slip nuts by hand or with a wrench, and remove the trap to clear out whatever’s built up inside before reattaching it.

When to Call a Plumber

Skip the chemical drain cleaners if you have older metal pipes, since repeated use can corrode them over time. Call a plumber if more than one drain in the house is slow at the same time, which usually points to a clog further down in the main line rather than the sink itself, or if you’re dealing with a foul odor along with the slow drain, which can signal a venting problem.