Why Does Sink Gurgle

Why Does My Sink Gurgle?

That gurgling sound from your sink happens when air is being forced back up through the drain. It's your plumbing telling you that water isn't flowing freely somewhere in the system. Here's what's causing it and how to fix it.

Common Causes of a Gurgling Sink

1. Partial Clog in the Drain

The most common cause. A partial blockage — usually hair, grease, or soap scum — restricts water flow and creates negative pressure that pulls air back up through the drain, causing the gurgling sound.

Fix:

• Try plunging first with a Luigi's Sink Plunger — block the overflow drain with a wet rag first
• If plunging doesn't work, use a Flexisnake Drain Weasel to pull out hair clogs
• For grease clogs, try Amazon Basics Drain Cleaner Gel

2. Blocked or Missing Vent Pipe

Drain vents allow air into the system so water can flow freely. If the vent is blocked or the sink doesn't have proper venting, air gets pulled through the water in the P-trap instead — causing gurgling.

Signs it's a vent issue: The sink gurgles even when it's draining well. Other drains in the house also gurgle.

Fix: A blocked roof vent needs to be cleared by a plumber. If the sink lacks proper venting, an air admittance valve (AAV) can be installed under the sink as a solution.

3. Shared Drain Line Clog

If your sink shares a drain line with another fixture (like a dishwasher or washing machine), a clog in the shared line can cause gurgling in the sink when the other fixture drains.

Fix: Clear the shared drain line with a 25ft Drain Auger or call a plumber if the clog is deep.

4. P-Trap Issues

If the P-trap under the sink is partially blocked or incorrectly installed, it can cause gurgling as water struggles to pass through.

Fix: Place a bucket under the P-trap, unscrew the slip nuts, remove the trap, clean it out, and reinstall.

How to Diagnose Your Gurgling Sink

Bottom Line

Most gurgling sinks are caused by a partial clog — start with a plunger, then a drain snake, then a chemical cleaner. If the gurgling persists after clearing the drain, the issue is likely a blocked vent pipe and you'll need a plumber.