Do you have a gurgling bathroom sink that’s driving you mad? Gurgling drains, as common as they are, may indicate the beginning of serious plumbing problems. Or, it might be nothing at all.
Let’s talk about how to diagnose the problem behind your gurgling sink drain so you can resolve it.
In this PlumbingNav guide, we cover:
What you need to know about how to stop a gurgling bathroom sink
Common causes of a gurgling bathroom sink
How to stop a gurgling bathroom sink
Supplies you’ll need to fix a gurgling bathroom sink
What's In This Guide?
What You Need to Know About How to Stop a Gurgling Bathroom Sink
Before you get started, you should verify that the gurgling only impacts only the bathroom sink. If it only affects the bathroom sink and not other drains attached to your sewer line, you know the issue is localized to that particular drain and vent system
As a primer, learn more about gurgling sounds coming from your sink in the video below:
Common Causes When Your Sink Gurgles, But Drains Fine
Air can get into your air pipes thanks to an empty P trap or improper ventilation of your drain line. Let’s discuss this in detail.
Empty P Trap
Every bathroom sink drain has a drain trap, usually a P trap. A P trap typically includes a 2” deep seal. Deep seal P traps will have a 4” deep seal.
The trap prevents toxic (and stinky!) sewer gas from returning back into your home. To work properly, the trap must have standing water inside of it (one of the only times you want standing water in your pipes).
Usually, when you encounter a dry P trap it will occur due to evaporation, especially during hot spells or in a guest bathroom. However, P traps may become dry due to a leak or a clog absorbing the water. This is one cause behind what causes a smelly bathroom sink drain.
Improper/Faulty Ventilation Leads to Gurgling
All plumbing pipes require ventilation.
Your bathroom sink will have its own ventilation pipe before it connects to your main vent.
Plumbing ventilation comes with strict regulations regarding angles and pipe sizes. See the video below to learn how to properly ventilate a bathroom sink:
You may experience gurgling sounds when vent pipes get clogged or damaged,
Some fixtures use an air admittance valve, which makes pipe ventilation somewhat easier. If the valve becomes open or damaged, you may need to resolve that issue.
How To Stop a Gurgling Bathroom Sink
Stop the weird noises by trying these methods on how to stop a gurgling bathroom sink.
Method One: Clean the P Trap (Including a Home Remedy For Gurgling Sink)
First, you’ll want to clean the P trap.
If the issue results due to a clogged drain or blocked drain, you should use a drain cleaner to remove the clog from the P trap.
Many people swear by the common homemade remedy of vinegar and baking soda. This can help, but it won’t be as effective as something like Green Gobbler drain cleaner.
Alternatively, you can use a stronger chemical drain cleaner if the issue requires more power. Just keep in mind that caustic drain cleaners should be used sparingly, or they can contribute to expedited corrosion in older cast iron pipes.
If the P trap experiences a stubborn clog, you may need to remove the P trap with a plumbing wrench and clean it thoroughly before checking it for leaks and replacing it. Don’t forget to turn off the water to the sink using the fixture’s shut off valve, or you will get water everywhere.
If you find the clog extends beyond the trap, use a snake to fully resolve it. The best plumbing snake should be designed for your sink drain and have adequate reach to turn corners.
Method Two: Fix a Faulty Air Admittance Valve
If the P trap is clean and you still get gurgling noises, check the air admittance valve (if applicable). Most people use air admittance valves in areas that aren’t easy to connect to the rest of the plumbing ventilation system.
First, check that it’s not open.
If you notice it appears damaged or faulty, replace the valve yourself by removing the old one and attaching the old one.
This assumes that the admittance valve provided proper ventilation to the sink previously. See this assembly if you’re not sure what we are referring to.
Method Three: Flush Air Vent
If you use standard ventilation, you can try to flush the air vent to remove any clogs in the vent pipe. This applies to you when multiple drains throughout your home are impacted.
Keep in mind that flushing your air vent reaches intermediate-level DIY skills. Only proceed if you feel comfortable.
To clear plumbing vents, you will need access, usually through your roof. Then you will use a large plumbing auger, ideally with a corkscrew end, and feed it through your plumbing vent. This will clear any bird nests or other debris that might be blocking air.
Check out the video below for the basics on clearing a plumbing vent:
Method Four: Re-vent Your Pipe
Did your pipes always gurgle? Or start gurgling after ventilation work? You may need to revent your bathroom sink and fix the ventilation error, especially if the other methods didn’t work.
When venting your pipe, you will need to create a proper slope (⅛” per foot for pipes 3 – 6 inches long) and use large enough vent pipes so that they won’t clog (larger than 1 ¼”).
Once again, only perform the task yourself if you feel comfortable preventing your pipes properly and your area allows DIY plumbers to do the work themselves (some municipalities may require that you call professional plumbing services).
You’ll need a plumber’s wrench, also known as an adjustable wrench, to remove the nuts that keep the P trap in place.
For a bathroom sink, you probably want a smaller 8” plumbing wrench like the Duratech Heavy Duty Pipe Wrench. Although, larger wrenches should work in most bathroom sinks, too.
New Air Admittance Valve
If you know the problem lies with your air admittance valve, you’ll need to get a new one. You can find numerous models online, depending on the size of your drain and what other components may have been damaged, too. Here is an example.
For example, some people may only need the new air admittance valve alone while others may want the new air admittance valve along with a tee adapter.
FAQs For How to Stop Gurgling Bathroom Sink
Why does my bathroom sink make a gurgling noise?
Your bathroom sink makes gurgling noises due to air in the pipes. Reasons you may experience air in your pipes include:
Clogged P trap
Dry P trap
Faulty air admittance valve
Clogged vent pipe
Improper ventilation
How do you clear a gurgling sink?
To clear a gurgling sink, you need to get the air out of the drain.
If the problem only occurs at your bathroom sink and the sink didn’t google before, you probably need to clean the P trap and restore it with water.
Why does my sink gurgle when not in use?
Air bubbles in your drain may occur even when the sink is not in use, causing gurgling noises.
How do you fix a gurgling pipe?
To fix a gurgling pipe, clean the drain trap. If that doesn’t resolve the problem, replace the air admittance valve or clear your vent pipes.
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About Plumbing Navigator
We write about "all things plumbing," helping you navigate common questions, repairs, and the best plumbing products on the market.
About Plumbing Navigator
We write about “all things plumbing,” helping you navigate common questions, repairs, and the best plumbing products on the market.
