If you hear a gurgling noise coming from your kitchen sink when you flush the toilet, it can be annoying and seem like a plumbing problem. But don’t call the plumber just yet! This issue is usually an easy fix.
In this article, I’ll explain why your sink gurgles when the toilet is flushed, the causes of the gurgling sound, and several ways you can fix this issue yourself without needing a professional. With a few simple solutions, you can stop your sink from gurgling and keep your pipes and drains flowing smoothly.
Why Does the Sink Gurgle When You Flush?
First, it helps to understand what causes the gurgling in the first place. When you flush the toilet, a large volume of water flows down the drain. This creates negative air pressure in the main sewer line that carries waste from your home. As air tries to release this negative pressure, it can bubble up through the water in your sink p-trap, making the gurgling sound.
The p-trap is the curved pipe underneath your sink that holds water to prevent sewer gases from escaping. When another plumbing fixture like the toilet flushes, it displaces air that then travels through your pipes looking for the easiest way to escape. This air pressure release makes the water in your sink p-trap bubble and causes the gurgling noise.
10 Ways to Fix a Gurgling Sink When the Toilet Flushes
Fortunately, a gurgling sink usually isn’t a sign of a major plumbing problem. There are several easy ways you can try to fix this issue yourself:
1. Check for proper venting
Proper venting allows air to enter the plumbing system so water can drain without suctioning air from the sink p-trap. Make sure your drain has a vent pipe that runs to the main vent stack. If not, call a plumber to install one.
2. Clear drain clogs
A clog in the kitchen pipes or drain could be blocking proper water flow and lead to air getting sucked through the p-trap. Try plunging the toilet and using a sewer auger on sink and main drain lines.
3. Install a cheater vent
A cheater vent provides extra venting directly below the sink to prevent gurgling. This small air admittance valve is easy to install yourself.
4. Check for proper p-trap installation
Make sure the p-trap under the sink is properly installed and creating a tight water seal. If not, tighten or reinstall the pipes.
5. Flush wastewater down another drain
Run some water from a sink, shower, or hose down another drain while you flush the toilet to release pressure on the kitchen pipes.
6. Seal pipe connections
Look for loose or leaky drain connections that could let air escape. Use pipe sealant to tightly seal any gaps.
7. Update old pipes
If you have old metal pipes, they may be misaligned or corroded, allowing air to pass through. Replacing with PVC can help.
8. Give it time after a new install
If this started after new construction or plumbing work, wait a week for the pipes to fully settle before taking action.
9. Check the main sewer line
Root damage or broken pipes on the main line can also cause improper drainage. You may need to use a sewer auger or camera inspection.
10. Call a plumber
For chronic gurgling or if none of these solutions do the trick, it may be time to call a professional plumber to inspect and fix the problem.
What To Remember About Fixing a Gurgling Sink
While it can be annoying, a sink that gurgles when the toilet flushes is usually an easy fix:
- The gurgling is caused by air pressure changes when large volumes of water drain
- Proper venting, drain clearance, and p-trap installation are key to preventing it
- Simple solutions like cheater vents, augering drains, or updating pipes can stop the noise
- For chronic issues, you may need plumbing repairs to pipes, vents, or the main sewer line
Don’t live with the nuisance of a loud gurgling sink – try these DIY solutions to fix the problem yourself. But when in doubt, call a professional plumber to inspect and address the cause of your gurgling sink. With the right repairs, you can drain your sink and flush your toilet in peace.
