How to Fix a Gurgling Bathroom Sink [5 Tips to Find and Fix]

To stop your bathroom sink from gurgling, start by addressing the most common cause—a clogged pipe. Use a drain snake to clear any clogs caused by hair and debris. Then, use a commercial drain cleaner, followed by a foaming drain cleaner made from vinegar, boiling water, and baking soda.

If these solutions do not work, the cause is most likely a faulty P-trap or a clogged vent pipe. If your P-trap is not broken and is not clogged, then it may have been installed improperly, which requires professional replumbing. A clogged vent pipe can be cleared by going onto your roof and removing any debris from the top of the vent. If it is unsafe to go onto your roof, contact a professional plumber for assistance.

Why is Your Bathroom Sink Gurgling?

Gurgling bathroom sinks are most commonly caused by a partially clogged sink drain pipe. The water drains slowly, which leads to a gurgling or “gulping” sound. A partially blocked sewer drain can also cause your bathroom sink to gurgle. If a clog is not the issue, a leaking, broken, or improperly plumbed P-trap may be the cause. A P-trap that allows sewer gas to flow back up from the drain can cause gurgling.

• A partially clogged sink drain.
• A clog or blockage in your sewer drain.
• The sink’s P-trap is not functioning properly.
• The vent pipe for the sink is partially blocked.

The final common cause of a gurgling bathroom sink is a clogged vent pipe. All drain pipes are designed to vent air and gases from vent pipes, which typically exit on your roof. If this vent is clogged, air can be trapped in your pipes and exit from your sink, which leads to the telltale gurgle.

What Happens if You Don’t Fix a Gurgling Sink?

A gurgling sink can become something much worse if the issue is not addressed. A gurgle caused by a partial blockage can easily turn into a fully clogged sink that does not drain at all. If the gurgle is caused by a faulty P-trap, sewer gas can flow up into your home. This gas is foul-smelling and can cause headaches and nausea.

• The sink could become fully clogged.
• Sewer gas could flow into your home.
• A gurgling sink problem is not likely to resolve on its own.

If your bathroom sink’s gurgling problem is caused by issues with the vent stack, then the issue can get worse. Sewer gases that should be emitted from the vent can instead flow back into your home. This can result in similar bad smells caused by a malfunctioning P-trap.

5 Steps to Diagnose and Fix a Gurgling Bathroom Sink

Because there are several possible causes of a gurgling bathroom sink, it’s essential to use a process to eliminate the most common causes first. By following this process step-by-step you will use easy fixes that can stop sink gurgling, then move to fixes for less common issues.

Snake the Drain

Because the gurgling sound coming from your bathroom sink may be caused by a drain clog, begin by snaking the drain. A flexible plastic drain snake is great for unclogging sinks. Simply feed the entire length of the snake into the drain and rotate it fully 4–5 times. Then, pull the snake out of the drain. Remove any hair and debris from the snake and repeat until the snake comes out clean.

• Use this drain snake to remove clogs in your sink’s drain.
• Feed the drain snake fully into the drain, then rotate the snake in a circle several times.
• Remove the snake, clean off any hair and debris, and repeat until the snake no longer pulls out debris.
• After this step, run the water in your sink. If the drain continues to make a gurgling noise, move to the next fix.

If the stopper in your sink makes feeding the snake into the drain difficult, try removing the cap on the stopper. Rotate the top of the stopper counterclockwise. If it spins freely, it may unscrew to make unclogging your sink easier. If there is strong resistance when you attempt to unscrew the stopper cap, stop. Forcing the issue may break the stopper in your sink.

Use a Clog-Busting Drain Cleaner

Sometimes, the gurgling sound coming from your drain can be caused by a clog that is lodged too deeply in the drain pipe for an ordinary drain snake to reach. In this case, it is best to use a commercial drain cleaner to attempt to resolve the issue. Use a gel drain cleaner and follow the directions on the packaging to clear the drain.

• Use this gel drain cleaner to break up drain clogs that cannot be reached by regular plumbing snakes.
• Follow manufacturer instructions and safety precautions when using any commercial drain-cleaning product.
• After the drain cleaner has been given time to work, run the water in the sink to determine if the gurgle has disappeared.

We prefer to use gel-type drain cleaners because the thicker solution moves slowly through the pipes, breaking up clogs. It’s also a good idea to get two bottles of drain cleaner and use them back-to-back to be sure the clog is destroyed. Then, run the tap and listen. If you still have a gurgling drain, move to the next method.

Create a Homemade Foaming Drain Cleaner

If commercial drain cleaners don’t work to stop your sink’s gurgle, there’s still one more inexpensive, powerful fix you can try before you start taking apart your pipes. All it takes is baking soda, hot water, and vinegar. Just follow these steps:

• Pour 1 cup (125 g) of baking soda into the drain.
• Bring 3 cups (700 ml) of water to a rolling boil.
• Add 3 cups of vinegar to the boiling water.
• Carefully pour the vinegar and water mixture into the drain.
• Allow the foaming mixture to work overnight.
• Run your sink in the morning to see if the gurgling has ceased.

This homemade drain cleaner uses the reaction of baking soda and vinegar to create a hot, foamy drain cleaner that is powerful enough to bust apart clogs and destroy soap scum in your pipes. If you’ve followed the first 3 methods and your sink is still gurgling, it’s time to get serious.

Remove and Check Your P-trap

Is your gurgling sink also releasing foul odors into your bathroom? This could be a sign of a malfunctioning or leaking P-trap. If you’re not sure what a P-trap is or why it’s necessary, check out our guide to understanding P-traps. Then, if you’re feeling up to a little plumbing work, take these steps to remove the P-trap (also called the U-bend) under your sink.

• Shut off the flow of water to the sink by closing the valves on both the hot and cold water lines under the sink.
• Locate the pipe fittings above and below the P-trap. They will be the ridged collars on the pipes, before and after the U-shaped section of pipe.
• Loosen the pipe fittings holding the P-trap in place by turning them counter-clockwise.
• Slide the pipe fittings away from the joints connecting the pipes.
• Gently remove the U-shaped section of pipe.
• Make sure the P-trap has water held inside the U-bend.
• Check the P-trap for cracks, leaks, and clogs.
• If the P-trap is clogged, clean it and put it back into place.
• If it is cracked, leaking, or did not have any water in it during removal, replace the P-trap yourself.
• If you do not feel comfortable with tackling this work, contact a professional plumber for assistance.

A leaking, cracked, empty, or clogged P-trap can cause your sink to gurgle. This is because air trapped in the bend will race up and out of your sink. A P-trap is meant to hold water in the U-bend and should never be empty. Sometimes, a P-trap will not hold water if it was improperly plumbed. If this is the case, the sink should be repaired by a licensed plumber.

Check Your Vent Pipe for Clogs

The final common cause of a gurgling sink is a clogged vent pipe. To check if this is the problem, climb onto your roof and locate the vent that is releasing air from your bathroom sink. Check the vent for debris that is clogging it. Sometimes, nesting birds or other animals can clog the vent pipe with leaves and twigs, which results in a gurgling sink. Remove the debris and check your sink, to see if it still gurgles.

• Use a ladder to safely climb onto your roof.
• Locate the vent pipe releasing gases from your bathroom sink.
• Check the vent for clogs, such as from bird nests or dead leaves.
• Remove any debris present in the vent.
• Recheck your sink to see if the gurgle is fixed.
• If the sink still gurgles, work with a professional plumber to correct the plumbing issue.

Only climb onto your to check the vent pipe if you can do so safely. It is best to have an assistant on hand in case anything goes wrong. If you don’t feel comfortable going onto your roof—or you do not have a helper—do not attempt this fix. If your bathroom sink is still gurgling, reach out to a licensed plumber to help resolve the problem.

How Do You Stop Your Bathroom Sink from Gurgling?

If your bathroom sink has a nagging gurgle, you can often correct it yourself. Here are the steps you should take to eliminate possibilities and solve that pesky gurgle:

• Snake the drain to remove any clogs.
• Pour a gel drain cleaner down the drain to break up deep clogs.
• Use a foaming drain cleaner made of baking soda, vinegar, and boiling water to clear clogs overnight.
• Remove and inspect your P-trap for clogs, cracks, and leaks—replace it if necessary.
• Clear debris from the vent pipe on your home’s roof.

These steps will help you rule out simple causes of a sink gurgle. Then, you can take more advanced steps to solve problems with P-traps and vent stacks. This plumbing knowledge can help you get rid of that obnoxious gurgle in your sink before it becomes something worse.