How to Unclog a Toilet That’s Backing Up Into the Bathtub: Tricky but Possible

Having a toilet that backs up into the bathtub is a problem that emerges when clogs form down the line. Since usually sewer waters go just one way – down the drain, this indicates something deeper down.

So when the question of how to unclog a toilet that’s backing up into the bathtub arises, this is not an ordinary job to do. If that’s your case and you need to solve it, prepare some equipment and be ready to get your hands dirty for a while. It might take some special effort, but everything can be done.

Guide on Unclogging Toilet That’s Backing Up Into Bathtub

If you suddenly see your clogged toilet backing up into the tub, that’s an unpleasant experience. The reason is a clog that formed somewhere deeper down the drainpipe. If your bathroom tub and toilet won’t drain, it’s time to check whether you can solve the issue on your own or have to call a plumber.

“Backing up”: What does it mean?

When you flush your toilet, the waste is supposed to go down the drain and never come back. So it happens normally. If a clog forms in the toilet or right after it, the water just won’t go from it, and you need to use a plunger that usually helps. But what if you have a clog deeper down the drainpipe after both toilet and bathtub exit pipes?

As a result, when you flush the toilet, the sewer waters rise through the bathtub drain. Not only does it mean some unpleasant smell and dangerous bacteria that sewer waters have in excess. It also means the impossibility of normal flushing, so you have to take measures as soon as possible.

Probable causes and solutions

There are various reasons causing sewage backing up into the shower or bathtub.

Mild blockage

This can be a result of mineral deposits that grow slowly inside the tube. This sort of blockage develops for years, but if you neglect it, one day, it can take lots of effort and money to prevent.

How to solve: pay attention if flushing gets too slow and use methods from the FAQ section. Yes, even a portion of dish soap or Epsom salt can keep it from aggravation.

Sewer line blockage

This can happen if improper items get into the drain system and block it. These can be large ones or lots of smaller ones, like bits of toilet paper, hair, or soap pieces.

How to solve: if the plunger does not help, you can use a plumber’s snake – a hard cable with a cone-shaped auger at the end. This item solves the question of how to unclog the toilet and bathtub drain in most situations. Its applicability, though, is limited by its length.

sewer line

Vent blockage

The waste that forms the clog can come from your plumbing vent that’s connected to the drainpipe. Though vents usually have some protection from waste getting in, it doesn’t always work.

It’s this case if it’s the air backing up your bathtub, not water. This also results in an unpleasant smell of rotten eggs; this is hydrogen sulfide which is not just unpleasant but toxic.

How to solve: usually this is a rather mild clog that might even not reach the pipe. To remove it, you need to reach the exit (which is usually on the roof) and have your assistant flush the toilet.

If you feel no suction while flushing, the vent is clogged. Use a plumber’s snake or a garden hose to unclog it. If it’s impossible to reach its top exit, you can make one in a PVC pipe somewhere indoors and do the same.

plumbing vent

Drain stack blockage

This happens when it’s not your internal sewer line that’s clogged but the main drain stack of the house or even the output sewer line behind it. If so, you need to call a plumber, because it results in much more than just a toilet and bathtub clogged.

You might feel tempted to use some chemicals to do it yourself. But the only tool that really helps in such a situation is your phone. Still, you can only diagnose it if no other methods help.

Tips on further prevention

Sometimes the clog down the drainpipe can be prevented by keeping from things that you habitually do while you better not. These things include:

  • Throwing the toilet paper into the toilet after usage. You better have a special bucket for used toilet paper;
  • Flushing kitty litter down the drain. It seems an easy solution if you share your toilet with your cat or any other animal. But the price of this ease can be too high;
  • Throwing any other objects down the drain if they are not supposed to be disposed of that way;
  • Ignoring slow flushing. If you notice that your waste goes down the drain too slowly while the toilet flushing mechanism functions normally, it might be the first sign of partial clogging. It’s easier to take measures before it grows full.

You should be especially careful if there are little kids in your family. They can throw any unexpected thing into the toilet and flush it down, to your frustration and plumbers’ fun when they find it.

toilet clogged with paper

FAQ About Unclogging Toilet That’s Backing Up Into Bathtub

As the topic raises interest from everyone who has a bathroom with a toilet backing up into the shower, there are extra questions about it. Here are the answers to some of them.

What will dissolve toilet paper in a sewer line?

There are some substances that can possibly dissolve a clog of toilet paper. If you are sure about the culprit, you can use a mix of vinegar and baking soda. Other methods include RID-X, Epsom salt, or dish soap, which deserve a separate question.

How much does it cost to unclog a main sewer line?

This work usually requires a professional plumber’s assistance. If they do it with the snake, it might cost between $150 and $500. Stronger methods, like hydro jetting, start at $250 and might cost up to $800. The range can be even wider in atypical situations.

Will dish soap unclog a toilet?

Chemical methods are the last resort. A good bit of dish soap, though, is a good method. Knowing how to fix a toilet backing up into the tub with a bit of dish soap can save you some money and time.

You must know, though, that it works best with hot water. First, pour the dish soap into your toilet bowl, and then add about a gallon of hot water that almost boils. This combination softens local clogs in 10-15 minutes. If it doesn’t, the problem is way deeper.

bottle of dish soap

Does Coke clear the blocked drain?

There are numerous urban legends about the cleaning virtues of Coca-Cola. Its effectiveness to remove corrosion, though, is proven. I had an experience with surfaces that I couldn’t steer clear using anything else but Coke.

Sometimes it works for unclogging as well. But it’s recommended to use at least two liters of Coke and after an hour or two, again, drain with boiling water. A good and affordable method but it might take too long.

Also read:

It’s Now O’Clog!

Knowing how to unclog a toilet that’s backing up into the bathtub is not a guarantee that you can do it on your own. On the other hand, if you tried all the methods and found out you cannot, it’s time to get off the dead horse and call a plumber.

If you encountered such a problem, it would be great of you to share your experience in the comments. Maybe, you know some ancient secret or invented your own one? Let’s help each other by sharing knowledge.

Gerald Carpenter

My name is Gerald Carpenter and I am a professional plumber in the third generation. My father was a plumber, my grandfather was a plumber. I wish I had records on my other ancestors.

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