How to Fix a Toilet That Bubbles and Gurgles When Flushed

Get your toilet and water pressure working right again with these easy steps

Co-authored by Allen Lee and Eric McClure

Last Updated: February 17, 2023 References

Diagnosing the Problem

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Clearing a Blocked Toilet

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Unclogging a Vent Stack

If you’ve noticed bubbles come up or you hear gurgling in your pipes after you flush your toilet, it’s a sign that the water isn’t draining properly. Don’t worry—this is an easy-to-fix problem. Your home plumbing system has 4 components: the water main that brings water in, the main drain that takes it out, all the plumbing pipes in between the main and the drain, and the vent stack that allows air into the whole system so the water flows freely. Gurgling is a sign the pressure is off, so the issue has to be with the flow of air in, a blockage in the pipes, or a problem with the flow of water out. Once you find the blockage, clearing it is a breeze! In this article, we’ll walk you through the entire process from beginning to end.

Things You Should Know

Identify the location of the problem by monitoring the tub and sink closest to your loud toilet and testing the drains elsewhere in your home.
Plug the other drains around your home and then plumb the toilet or snake it with a drain auger to clear the blockage.
Clear the vent stack on your roof by removing whatever’s blocking the pipe or filling the stack up with water to flush it out.

Method 1

Method 1 of 3:

Diagnosing the Problem

1
Run the water everywhere in your home to isolate the problem. If the gurgling is isolated to a single toilet, that single toilet needs to be unclogged. If you notice a set of toilets, sinks, and/or tubs are having a similar issue, then it’s a clog in your drain line, but deeper down. If all of your drains are bubbling, gurgling, or struggling to drain, the issue is your vent pipe.^{[1]
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- There’s a fringe possibility that your vent pipe is clear and all of your drains are gurgling because your city’s sewer system is blocked.
2
Flush the gurgling toilet and check the nearest drain for water. Flush the gurgling toilet a few times and take a gander at the nearest tub and/or sink. Do you see water coming up? If you don’t, the blockage is in your toilet and this should be an easy fix. If water is coming up though, it could be your main drain line or the vent stack and you’ll need to investigate further.^{[2]
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- The water flowing back out elsewhere means the blockage is deeper than the point where your toilet drain and the tub or sink drain meet up with the main drain line or the vent stack is clogged and the water can’t flow correctly.
- If your home has a septic tank, that could be the culprit instead of the main drain line.
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3
Check your septic tank to look for leakage and ensure it’s working. Go to wherever your septic tank is located and look around. If you see puddling, flooding, or hear wastewater dripping or flowing, your septic tank is overfilled. Maybe it just needs emptying or maybe the pump has failed. In either case, it’s not a DIY job. Contact a septic tank service to empty the tank and make any repairs as needed.^{[3]
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- Expect to pay as little as $200 for a tank emptying or roughly $1,700 to repair a damaged tank.
4
Talk to your neighbors to see if they have similar issues. If your whole home is having issues draining or you hear the gurgling everywhere and see small bubbles in other toilets, reach out to one of your neighbors and ask them if they’re having any plumbing issues. If they’re experiencing the same issues you are, you’re in luck—this is your city’s problem. Call your local water department and tell them the sewer line is blocked.^{[4]
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- If you don’t have a septic tank, your water is hooked up to your city’s water lines. The fact that more than one home is having issues means the problem has to be the main drain.

Method 2

Method 2 of 3:

Clearing a Blocked Toilet

1
Plug the nearby sinks, showers, and bathtub drains. If you know the problem is deeper than your toilet’s main drain, plug the closest drains. If you don’t have stoppers for any of the drains, unscrew or remove the cover and stuff a balled-up rag or plastic bag inside. This will help dislodge deeper blockages.^{[5]
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2
Use a plunger to unclog the toilet with the problem. Grab a plunger and set the bulb inside of the hole in your toilet. Repeatedly push down to force air into the drain pipe. This should clear any minor blockages that are causing your issues. You won’t see the air bubbles when flushing the toilet anymore.^{[6]
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- FYI, toilet plungers have a flange on the bottom of the bowl. The plungers that are flat at the bottom are designed for sinks.
3
Snake the toilet if the plunger doesn’t do the trick. If you still notice the gurgling in the toilet, buy a drain auger (aka a snake) or borrow one from a friend. Extend the end of the drain auger and feed it into the toilet. Continue to extend the line until you run into resistance, then force it further down to dislodge the block. Retract the line and flush to confirm the problem is solved.
- Your drain goes deeper than your basement, so use an auger that can go that far. If you’re on the first floor, you probably only need 15–20 feet (4.6–6.1 m). For a third-floor bathroom or higher, you may need an auger that’s up to 100–150 feet (30–46 m) long.
- There are electrical drain augers out there, but they’re meant for professional plumbers. You don’t need a $100+ snake to do this.
4
Pour drain cleaner in the toilet to clear mineral buildup. In fringe cases, mineral buildup inside of the pipes can cause symptoms that are identical to a blocked pipe. If snaking the line and plunging it doesn’t work, pour any commercial drain cleaner down the drain by following the instructions on the container.^{[7]
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- This is more likely to be the case if your home is especially old and the pipes haven’t been worked on in a long time.
5
Clear out the nearest drains if snaking the toilet was ineffective. It’s possible that you simply misidentified the location of the blockage, or that the blockage is in a really counterintuitive location. If your toilet is still bubbling, try plunging and snaking the nearby tub and sink. If you run into resistance and successfully remove the blockage, it should fix the problem with your toilet.^{[8]
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- If you still can’t get your toilet to stop bubbling, either check your vent stack or call a plumber.

Method 3

Method 3 of 3:

Unclogging a Vent Stack

1
Get on your roof and look for your vent stack. If you cannot get safely on your roof, you’ll have to call a plumber to fix this problem. Your vent stack, or vent pipe, is an open pipe that sticks out of your roof. It lets air get into your plumbing system so that the water flows freely. If it gets clogged by something though, it will make it difficult for the water in your home to drain out. However, if you don’t have access to your roof or your roof is pitched, call a plumber—it’s not safe (or easy) to work on a roof if you don’t have experience.^{[9]
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- Without air coming into the system, the air that’s already in your pipes has nowhere to go. This increases the pressure in the entire system and increases the odds of a burst pipe.
- Your vent stack is the 3–6 in (7.6–15.2 cm) wide pipe that sticks up from your roof and points straight up. Your home may have multiple stacks.
2
Pour boiling water down the vent if it’s freezing out. Vent stacks have an unfortunate habit of freezing up in the winter, and when that happens, snow can accumulate inside. If you can access your vent stack safely, boil some water and take it up to your roof. Pour the boiling water down the vent slowly to thaw any ice can create an opening.^{[10]
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- Don’t worry—you won’t damage the pipe by doing this. Plumbing pipes can handle the super-hot water from your shower, after all.
- You may need to do this multiple times to fully thaw the pipe.
3
Retrieve visible objects trapped inside with a coat hanger. Use a strong flashlight to inspect the pipe for a clog. If you can see what’s blocking the pipe, grab a wire hanger to pull out whatever is stuck. Usually, it will be a clump of dead leaves and foliage, but it could be a dead bird or something else of the sort.^{[11]
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- If you can’t reach it with an unwound wire hanger, you can use a long stick or something of the sort.
- If it’s too far down for you to reach, don’t worry. There’s another solution.
4
Wash the clog down if you can’t reach it using a garden hose. Run a hose up to your roof and turn the water on. Begin to fill up the vent with water. Don’t worry if it overflows. Either keep the hose running for 5-10 minutes or let the vent stay full of water. Eventually, gravity and the weight of the water will do their thing and the blockage will slide down into the plumbing system where it can slide out.
5
Snake your vent stack pipe if the water won’t drain. If you still can’t clear the blockage and the water won’t go down, grab a drain auger. Snake the pipe the same exact way you’d snake a clogged toilet. Once you break up the blockage, the water will go down. The blockage will flow out through your sewage system and you’re ready to go.^{[12]
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