Bathroom Sink is Backing Up (What You Should Do)

Slow draining bubbling bathroom sinks are annoying. Not only does water drainage take forever, but it also leaves scummy deposits that you have to wipe out of the sink. Or worse, no one wipes the sink.

Most people assume that bathroom sinks will just accept all of the stuff dumped into them–hair, soap, teenage daughter’s makeup (troweled on and off)–and continue to drain. But sometimes they will plug up and need some help.

Most bathroom sink drainage repairs are fairly simple. They require few tools. Cleaning your sink drain is usually inexpensive and quick. If done properly, cleaning is not even too messy. Also, if you look on the bright side, it could be much worse. Your whole bathroom could be flooded.

Hopefully, the following suggestions will help you keep your bathroom sink running freely.

What Causes Water To Back Up Into the Bathroom Sink?

The most obvious cause of a backup in your sink is clogged drain pipes. Think of all that you do over your bathroom sink. Washing. Shaving. Tooth brushing. Hair styling. And all that gets poured into it.

Hair is particularly efficient at collecting and binding soap, toothpaste, and makeup oils into something nasty. P-traps and ABS plumbing pipes are fairly smooth but things dropped into the drain can form sediment and adhere to the pipe. 

By design, P-traps hold water to create a plug that keeps sewer gas odors from entering the house. Stagnant water also makes it easier for soap scum and toothpaste-filled hair to stick to the pipes.

A less obvious cause of water–or something worse–backing up into your sink is blocked airlines. All plumbing requires incoming air to flush and drain properly. If these pipes or stacks are plugged, the system will try to draw air from other sources. The result can be sewage or bathtub water coming up into your sink.

Signs of a vent blockage include smelling sewer gas and gurgling sounds coming from the drain. These are signs that something–like flushing the toilet–tries to draw air from the sink drain and sucks the water out of the P-trap.

Clearing Blocked Bathroom Sink Drains

Drain blockages usually occur within 2 feet of the sink outlet. In the pipes, the P-trap, or the pop-up drain plug. You can usually identify a clog by filling the sink with a pail of warm water. If it drains slowly and bubbles, you likely have a clog closer to the drain.

Use a Plunger on Your Sink

The quickest and easiest way to clear clogged sink drains is by using a small plunger. You will need one with a short handle and a small cup. Your toilet plunger will probably not work.

Inexpensive Homemade Drain Cleaner


  • ½ cup baking soda
  • ½ cup vinegar
  • 2 quarts boiling water

Make sure the sink and drain are empty of water. Pour all of the baking soda into the drain followed by all of the vinegar. Plug the drain and wait at least an hour. (Longer is better.) Open the drain and slowly pour boiling water down it. 

In most cases, your drain should clear out and work better. If it still drains slowly you may have to try one of the other ideas.

Clear your Bathroom Sink With a Snake

Snake is another name for a plumbing auger. Plumbing snakes are a coil of wire with a pigtail end that can be shoved through plumbing pipes to eliminate clogs. The end will either loosen the clog and move it along or it will snag clogs and pull them back out.

Most snake pigtail tips are around ½” in diameter and are designed to clean out pipes between 1 ¼” and 3” in diameter. If you have a pop-up plug you will have to remove it to insert these types of snakes. The newer plugs can just be lifted out. If your plug has a rod, you will have to remove it. (Please see the video for removal information.)

Standard snake length is around 25’. Commercial snakes can be much longer. There are short inexpensive 18” snakes with disposable ends that are ideal for bathroom sinks and tubs. They are also small enough to be inserted in drains with pop-up stoppers.

Courtesy: Artic Eagle Amazon

Disassemble the Bathroom Sink Drain

Taking apart a bathroom sink drain is a fairly simple job as the following YouTube video illustrates. If none of the other suggestions work, you will have to remove the P-trap and drain stopper and clean them.

How to take apart and clean sink drain

If you don’t have a pop-up drain plug, the job is even easier. Removing and thoroughly cleaning the P-trap and pipes can help reduce future clogs. 

Eventually, most bathroom sink drains will need to be taken apart and cleaned. Having access to the P-trap and adjoining pipes is the only way to ensure you have cleaned it all. 

Note: Plugs with rods usually clog up quicker and easier because of the rod and holes in the stopper rod.

Call a Plumber

Whether you do not like clearing drains, you have no time, or you just can’t do it, calling a plumber is always an option. It will cost more money, but the job will be done properly. You will also probably have a warranty for the cleaning.

If your drainage problem is a clog further down the line, or a clog on municipal property, or a collapsed pipe, or a clogged air intake pipe, having a plumber look at it could be the best option. Unless you have the experience and equipment, some of these repairs can be a little daunting.

Some plumbing companies offer and recommend a yearly service package. They will come into your house and check drainage, incoming water, hot water systems, and whatever else you agree to in the contract. Make sure that cleaning bathroom sink and kitchen sink drains is included.

Anything that needs repair or attention can be dealt with while the installer is there–saving you the cost of an extra trip.

End Notes

A little preventative maintenance goes a long way to keeping the drains running. 

  • Try not to brush your hair over the sink. Or make sure it is cleaned out before running down the drain.
  • No makeup powders and oils should be run down the drain. No cotton or Q-tips.
  • Make sure that all of the toothpaste is run through the system.
  • Only flush what is meant to be flushed down the toilet to prevent main sewer line clogs.
Bathroom Sink is Backing Up (What You Should Do)
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