A gurgling toilet can be a nuisance, but it’s usually an easy fix. Here are the most common reasons why your toilet might be making noises and how to stop the gurgling for good.

Clogged Vent Pipe

The vent pipe is the curved pipe that extends out of your roof. It allows air into the waste system so water can flow properly. If it becomes clogged with debris, it can’t do its job. Air gets trapped in the pipes, causing that distinctive gurgling sound.

Clear out the vent to restore normal toilet function. Carefully climb onto the roof and snake the vent pipe to dislodge any blockages. Leaves, nests and other material often collect there. Once clear, the gurgling should stop.

Drain Blockage

A partial clog in the drain itself can also lead to gurgling. When waste can’t flow freely through the pipes, it causes bubbles and water turbulence that manifest as noises.

Plunging the toilet vigorously will often dislodge minor clogs. Use a closet auger if plunging doesn’t work. Insert the flexible rod down the drain and twist to hook and remove debris. For stubborn obstructions, try a chemical drain cleaner or call a plumber.

Improper Venting

If the vent stack isn’t installed properly, it can’t provide the air circulation needed for waste to drain smoothly. This is most common in older homes that have had remodeling or construction done improperly.

A plumber can inspect the venting and make adjustments if needed. Installing a new vent stack will solve gurgling issues caused by poor venting. Proper venting prevents the glugging sounds.

Failing Flapper Valve

The flapper valve at the bottom of the tank is supposed to provide a watertight seal. If it becomes warped or deteriorated, it won’t seal completely.

Small amounts of water can then continuously trickle down into the bowl. The irregular flow creates gurgles. Replacing the flapper is an easy DIY project that takes just minutes. Match the new part to the original.

Water Level Too Low

After you flush, the water level needs to rise high enough to fully seal the opening between the tank and bowl. If the water line is too low, air can enter the system. Bubbles then get churned up as waste passes through, leading to gurgling.

Check the water level and adjust the float if needed. The correct level is typically about an inch below the overflow tube. If that doesn’t solve it, the fill valve might need replacing.

Sediment Buildup

Over time, sediment and mineral deposits can accumulate inside the toilet’s flush valves and pipes. This narrows the interior diameter, which can create turbulence in the water flow. The result is annoying gurgling noises.

Try clearing the deposits by pouring a de-liming solution into the tank and letting it sit. Then flush a few times. You may need to replace overly corroded internal parts to fully stop the noise.

Nearby Plumbing Issues

Sometimes the gurgling is actually coming from another fixture tied into the same drain line. For example, a clogged sink or bathtub drain can send water back up the shared pipe. That turbulence will cause bubbling in all connected drains.

Inspect sinks, tubs, showers and other nearby drains. Plunge or snake any you find clogged. Fixing another fixture’s drain problem often eliminates the toilet gurgling.

Main Sewer Line Clog

A main sewer line clog out near the street can also cause gurgling in toilets and other drains. Tree roots, collapsed pipes and accumulation of grease and waste can obstruct flow through the main line. All wastewater then has trouble exiting the home.

If you suspect a main line issue, call a professional plumber. They have specialized equipment to locate and clear blockages in the main sewer pipe. Once fixed, everything should drain silently.

FAQs About Gurgling Toilets

What causes air bubbles in toilet?

Air bubbles in the toilet bowl are usually caused by a partial blockage somewhere in the drain plumbing pipes. This allows air to enter the system. Other common causes are an improperly vented system, a faulty flapper valve, and low water level in the tank.

Why does my toilet gurgle when another drain is used?

Gurgling when another fixture is run points to a venting issue. All drains in the home connect and use the same vent. If it’s clogged, air gets trapped, and using any drain can cause gurgling sounds from the toilet bowl.

Is it bad if my toilet gurgles?

Occasional gurgling isn’t necessarily a problem. But chronic gurgling indicates issues you should address. A partial blockage allows sewer gases to come back up the drain. Over time, this can deteriorate your plumbing and potentially cause waste backup.

How do I unclog my main sewer line?

For a DIY approach, use a drain snake to clear roots, grease and debris from the main line. Insert either a hand crank or electric powered auger down the cleanout access and twist to scrub the pipe interior as you push towards the street. Avoid using harsh chemicals. For professional sewer cleaning, hire a plumber.

Why does my toilet make noise when I flush other toilets?

All toilets in a home are connected. When you flush one, it releases water down the main pipe. That surge of water can cause the next toilet to gurgle as pipes shake from the flow. As long as it’s just a brief gurgle, this is normal and no cause for concern.


A gurgling commode can certainly be a nuisance and lead to embarrassment when guests are over. Luckily, a bit of DIY troubleshooting can often track down the cause and stop the noise quickly. Clogs in the toilet, drain, vent or main sewer line are common culprits. Adjusting the water level, replacing valves and clearing vents also helps resolve many toilet gurgling problems. Call in a professional plumber if you need assistance diagnosing or fixing persistent glugging and bubbling coming from the toilet.