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How to Stop Toilet Gurgling at the End of a Flush

It is not bad enough that the bathroom as a whole is the source of rude noises, now the toilet is gurgling every time you flush. Just in time for the big party. 

Don’t get too excited. Gurgling toilets are usually not a sign of imminent disaster. But nor should it be ignored. The toilet is probably trying to tell you something, and you should listen and do something about it.

Fortunately, most causes of a gurgling toilet are fairly simple to remedy–once you know what is going on. Here are some of the most common problems along with a few DIY solutions.



What Can Cause a Gurgling Toilet?

1) Clogged or Partially Clogged Toilet

The most obvious place to look for gurgling problems is in the toilet bowl. A blocked or partially blocked toilet will not get rid of the stuff as it should. You will probably see bits of toilet paper, and/or other things floating in there after each flush. This is usually caused by flushing things down there that the equipment was not meant to handle–like Q-tips, feminine hygiene products, wipes, goldfish that got too big, or ashtrays full of butts and gum wrappers. You need to get everyone in the household to ‘Knock it off’.


2) Glop in the Water Supply

Glop is a highly technical term describing the stuff in your water, such as iron, undissolved solids, calcium, magnesium, etc. Contaminated water usually does not cause problems in the bowl–other than stains and making it difficult to clean. Water contaminants will adhere to the refill mechanism in the cistern that holds the water for each flush. The cistern will fill slower and gurgle or make other obnoxious noises as it tries to fill. 


3) Vent Pipes

Toilets do not flush in a vacuum. They need a supply of air to work properly. Which is where the vent pipe or stack comes in. Every toilet, sink, and tub in your house has an air intake pipe that is generally attached to one or more stacks that should extend through the roof and provide air to each drain. A clogged stack will make flushing difficult and noisy as the toilet tries to suck air into the system to replace the water. Sometimes it will gurgle, sometimes it sounds like a gulp as it is flushing. And when it is filling.

Sometimes the gurgling in your toilet is the sound of the clothes washer trying to suck air from anywhere in the system to drain. Not only will the washing machine gurgle, so will the toilet and maybe a few other drains.

Note: Most plumbing codes specify a 4″ stack. Older codes were 3″ and before that a 2″ stack was acceptable. I think that stack size increased as the number of drains in houses increased. It was not that many years ago that a ‘two toilet house’ was uncommon–at least among my circle of friends.


4) A Faulty Refill Mechanism in the Cistern

As mentioned above, faulty refill mechanisms can be caused by undissolved solids in the water supply. But they can also just be getting old and worn, the float can develop a hole, or they may just need an adjustment to fill properly. If you take the lid off the cistern and it looks like a lawn sprinkler at work, you might want to consider turning the water off and having a look at it.

Note: For more about quiet flushing, please see our article How to Quiet Toilet Flush.


5) Main Sewer Line (or Septic Tank)

Occasionally your toilet gurgling/flushing problems are outside the house–either with the line connecting your house to the main sewer line or with the municipal line itself. The line on your property can have all kinds of problems such as tree roots growing into the line, frost heaves collapsing pipes, faulty joints coming apart, etc. Main sewer lines usually run under streets so tree roots are not a problem, but frost, old age, faulty pipe are all possible.

Diagnosing these problems are difficult and/or expensive for the average homeowner. But if you have–or want an excuse to buy–a plumbing camera, you can take a look into your sewer pipes to either find the blockage or put your mind at ease that there is not one.

Note: A good camera with enough cable to reach will likely cost hundreds of dollars. Make sure you exhaust all other options before spending the money. Or consider calling a plumber.


How to Fix a Gurgling Toilet

Hopefully you now have an idea of gurgling causes. And we can try to get them fixed.


1) Toilet Plunging

Just as plugged toilets are the easiest to diagnose, they are usually the easiest and least expensive to fix. Sometimes you may be able to solve the problem by plunging the toilet the same way you always have. Or you might need to put in a little more thought and effort. If you cannot push the clog through the system, you will have to try to pull it back out. This requires a plunger that will suck things out of the toilet system. You will need a toilet plunger that will fit the opening properly and create a vacuum. Then use painter’s tape to seal the drains of sinks and tubs close to the toilet to keep air from dissipating the plunger pressure. (Note: Painter’s tape does not leave residue like duct tape.)

Six to ten powerful strokes will hopefully get things moving. If you get the clog pulled out, do not just flush it back down. It did not work last time. Dip it out. 

Note: Plunging your toilet is never pleasant, but you can make it less annoying by getting a long handle plunger and keeping your mouth closed during the process.


2) Turn the Snake Loose

If you are convinced your toilet is clogged and the plunger did not work, it could be time to try a drain snake like the DrainX Power Pro. This is an inexpensive tool that can be operated by hand or with a drill. It reaches 25 feet so will easily get through the toilet maze and well into the piping. 

If you have never used a snake before, it might be beneficial to start by using hand power while moving it further into the pipe. With any luck, when you hit the clog, your snake end will latch onto it and you can pull it out–ending your gurgling problem.

Running the DrainX out its full 25′ without finding anything leaves you with a decision. 

  1. Longer Snake. If you opt for a longer, more powerful, and expensive snake, you will have to remove the toilet to get proper access. In which case you will need a new wax ring–at least–when you replace the toilet.
  2. Call a Plumber. It may be time for a professional assessment.
  3. Other Fixes. I would try the following 2 or 3 fixes first. Before choosing # 1 or # 2.

Note: Some plumbing snakes will state explicitly that they are not for use in toilets. Double check before ordering.


3) Clean the Vent Pipe

Plumbing stacks extend through the roof to provide an air intake for the entire plumbing system. If it becomes plugged, not only will everything quit draining well and make funny noises, you will start smelling sewer gas which stinks and can eventually become dangerous.

You will need to get up on the roof to do this job. With luck you will find the obstruction close to the top of the pipe. If not, you may need a small powerful flashlight and maybe some strong string to lower it down to take a look. If your clog is close enough to the top, a clothes hangar can pick it out. If deeper down the pipe, you may have to be creative with a hook on a long stick, or even the snake you bought to unclog the toilet. Make sure you get it out

Once the clog is out, cover the stack with an Oatey Mushroom Vent Cap. It will keep most everything, like leaves, branches, rodents, and birds, out of the pipe and still allow fresh air in and odor out. If you live in a heavy snowfall area, you might want to extend the pipe to 2′ high if it isn’t already that length. A heavy snowfall combined with freezing rain can seal the pipe solid (It sure did our short pipe one winter.)

Note: I have seen suggestions that you should take the garden hose onto the roof, and spray the clog down and out the sewer. I am not sure that forcing a dead crow deeper into your plumbing system is the best solution.


4) Replace the Refill Mechanism

Whether the gurgling noises, or other weird sounds coming from your toilet refill mechanism are caused by glop in the water or old age, the only realistic solution is to replace it. Fluidmaster has been making plumbing replacement parts since 1957 and they will likely be able to provide parts for almost any toilet. Changing a toilet refill mechanism is about as easy as following the instructions that come with the parts. Just remember to turn the water off first.

The new valves do not look like the old ball float, but work more efficiently and take up less room, and will fit and last for years.


5) Check With the Neighbors

No, you are not asking them to help fix it. Ask them if they are having the same type of problems, because if they are, it may point to a larger sewer problem. The municipal system that you are all hooked into might have a problem. In most jurisdictions, after the sewer line and contents leave your property, the problem goes with it. 

But if your bureaucracy is anything like most others, you may have to become fairly adamant about the problem–maybe with your neighbor’s input also–to be taken seriously.


6) Call a Plumber

A lot of these suggestions are fairly DIY-friendly, but depending on circumstances–such as your vent pipe being 3 stories up on an 8/12 pitch roof–calling a professional may be the better choice. Yes, it will probably cost more. But they should have the expertise, experience, and equipment to get the job done quickly. And provide a warranty. Make sure you get at least a couple of quotes.

Note: Before getting too far into your DIY repairs, decide if, and when, you are going to call the plumber. Plumbers, like most of us unwashed tradesmen, tend to have little sense of humor when they arrive at a house to find the homeowner has made a hash of things. And expects a deal because he/she has ‘helped’ by taking it all apart.


Toilet Maintenance – Stop the Gurgling Before it Starts

Here are a few simple preventative maintenance suggestions that can help keep the toilet quiet.

  • Flushables. Do not flush anything except water, waste, and toilet paper. PERIOD. If you are using the plunger daily or weekly, you might want to give some consideration to thinner, see-through toilet paper. (You might. I won’t.)
  • Vent Cover. Protect the vent from foreign objects with an Oakey hard cover. Do not use cloth or wire mesh. (Think bird poop on a street light sensor, making them run 24 hours a day.)
  • Clean the Tank. Keep the toilet tank clean–not only for the good of your refill mechanism but also for the bowl and waterways. When you flush the water surges into the waterway built into the rim of the bowl and pours out of the holes on the bottom covering the complete bowl and washing everything away. Having uniform water distribution aids in flushing everything out of the bowl. Kiisiiso Automatic Toilet Bowl Cleaning Tablets are an inexpensive way to keep things clean and running well.
  • Inspection. Consider getting your plumbing inspected annually. This is a fairly inexpensive way to prevent large costs later.

Terry Schutz

I have worked as a contractor, sales person, and business owner in the construction industry for over three decades--mostly in home renovations and also as a home builder. I have been married to the same wife for 46 years. We have 3 children and 4 granddaughters. I have also been writing semi-professionally for about 20 years--construction articles, personal stories, and politically incorrect social commentary.

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