Why Your Toilet is Backing Up Into Shower – How To Fix

One of the worst scenarios a homeowner can face is sewage backing up into your home. When this happens, it is usually an indication that the main sewer line is clogged somewhere – typically underground. There’s not much worse than coming home from a long day at work only to discover that your toilet is backing up into your shower, but fortunately, I have several solutions outlined below that can help you remove that clog and get things moving again. 

Is Sewage Coming Up From the Shower Drain?

Sewage can back up into a shower drain for several reasons, but the symptoms of a main sewer line clog are the same regardless of the cause. 

An obvious symptom is when sewage backs up into your shower drain when you flush the toilet. Other drains in your home may be backing up as well. Even if no sewage is present, there may be foul smells coming from the drains, or they may be very slow to drain. Sometimes, a clogged main sewer line can also cause flooding in the yard. 

The good news is that you may be able to fix that toilet backing up into your shower with one of the tricks below. 

Fixing a Toilet Backing Up Into Shower

There are many options for clearing clogged drains and sewer lines, but it is tough to tell which one will work best for the type of clogged it and the type of plumbing you have. Below, I’ve suggested a few solutions you can try yourself before calling a professional to fix your toilet backing up into the shower. 

Plunge with Soapy Water

This remedy often works well for toilet and sewer clogs as dish soap breaks down organic materials and lubricates the pipes. Toilet clogs that back up into the shower are often caused by toilet paper, wipes, feminine hygiene products, and poop. If you think this is the cause of your sewage backup, try pouring a cup of dish soap down the toilet.

Follow that with a pan of boiling water. Use a plunger to encourage the soap and hot water further into the lines, which should break down the clog and move it along. You may need to repeat this process a couple of times before it works completely. Hot, soapy water also works well on kitchen sink clogs caused by grease and other organic materials. 

Note: Be sure to use the right kind of plunger for the type of drain you’re clearing. Sink and toilet plungers are not the same!

Drain Snake

Just like plungers, drain snakes come in different styles, and which one is right for the job depends on the type of drain you are clearing. They are readily available online just like this Ridgid Power Spin drain snake available on Amazon.com for around $50.

Toilet is Backing Up Into Shower

Manual sewer snakes work by twisting the snake like a corkscrew until you reach the clog. Once you have penetrated the clog, you twist the snake in the opposite direction to pull it out. 

Flat tape snakes are used for clearing clogs in pipes less than two inches in diameter. 

Power snakes run by a motor and are used to clear tough clogs and toilet closet snakes are made especially for unclogging toilets. These snakes are extremely flexible and able to navigate a toilet’s intricate plumbing. 

Lift Your Outside Drain Cover

If your toilet is backing up into the shower, it could be that your outside drain is blocked. This is a common occurrence, and it’s often easy to fix yourself. 

Locate your outside drain and lift the cover. You may be able to see the clog right away, but if not, use a straightened wire coat hanger with a hook at one end to fish around for the blockage. Pull out all the gunk and debris you can find, while avoiding pushing it further into the pipe. Once the blockage is removed, flush the drain with hot water. 

You can also try pouring boiling hot water down the outside drain to melt and dissolve the obstruction. A mixture of baking soda and vinegar is another blockage remover that works well to clear outside drain clogs, and the concoction is also a great maintenance cleaner to keep the drain flowing freely. 

Check Your Vent Pipe Is Clear

Many homeowners don’t realize that their plumbing is vented out through the roof of their homes. This vent is important as it keeps noxious sewer gasses from coming into your home. Sometimes, a plumbing vent can get clogged, causing sewage backup issues throughout the house. 

To check if a clogged plumbing vent is the cause of your toilet backing up into the shower, enlist the help of another family member. Climb up on the roof and locate the plumbing vent. Place your hand over the vent and have your assistant flush the toilet. If you feel suction on your hand, there is a clog in the pipe. Use a snake and/or garden hose to remove the obstruction and then have your assistant flush the toilet again. If this method is unsuccessful at removing the blockage, it’s time to call in a professional.

5 Reasons The Toilet is Backing Up Into Shower

As stated at the beginning of this article, there are several reasons a toilet can back up into the shower. Identifying the cause can help you choose the right method for fixing the problem. 

1. Not Enough Water in The Toilet Header Tank

When the toilet tank doesn’t have the proper amount of water in it, the toilet can’t do its job efficiently. There isn’t enough water to help push debris through the pipes, thus resulting in clogs that can cause sewage backup in the shower every time you flush the toilet. 

2. Household Object Stuck in The Trap

Your home’s plumbing is meant to move liquids and soft materials, not most household objects. The P-trap (the u-shaped pipe found under most sinks and behind toilets) is designed to stop unwanted objects from getting into a home’s plumbing. As such, the trap can become clogged itself, which can cause water to back up into other drains throughout the home. Fortunately, most P-trap clogs are easy to clear by simply removing that section of pipe and cleaning it out.

3. Blocked Interior Drain Pipe

The plumbing pipes that carry black and grey water away from your home are an intricate web of large and small pipes. They can become clogged with various materials if not cared for in the right way. 

Grease or Fat Build Up

Since grease and fat are liquids when hot, many people think they can simply pour them down the drain and they will flow away like water. Unfortunately, these fats solidify once cooled and can coat and clog pipes over time. 

Hair and Scum Build Up

Ask any man or woman with long hair and they’ll tell you how much they hate the amount of hair that ends up in the shower drain. If left in the drain, the hair collects soap scum and hard water deposits until the mass slows the flow of water or stops it altogether. The same applies to flushing hair down the toilet, this can also cause blockages and lead to the same outcome.

Excessive paper or wipes

Toilet paper is designed to dissolve in a home’s plumbing system. If someone uses too much at one time, however, it can clog the pipes. 

In that same vein, many people use flushable wipes to clean after using the restroom. Although the package says flushable, all that means is that they flush easily, not that they break down in the plumbing. Flushable wipes do not break down as toilet paper does, and they are the cause of many interior drain problems experienced by frustrated homeowners who didn’t know this.

4. Mineral Deposits

Older homes built before 1950 often have cast iron pipes in their plumbing systems. While cast iron is a very durable material, it is susceptible to rust and corrosion that can clog the pipes. 

Further, if your home has hard water (excess minerals such as calcium, iron, and magnesium) these minerals can build up over time in your home’s pipes, creating slow-moving drains and blockages that can be difficult to remove. 

5. Tree Roots

Because most of your home’s plumbing is located underground, it is susceptible to damage caused by infiltrating tree roots. It’s impossible to prevent this from happening as you likely won’t realize it as a problem until the damage is already done. The only way to fix a tree root problem with your plumbing is to dig up the clogged pipe and replace the damaged section. 

You may also be interested in reading Why Your Toilet Randomly Runs and How To Fix It

Toilet Backing Up Into Shower: SOLVED

A toilet backing up into the shower is a common problem many homeowners face at least once. The issue is usually caused by a blockage somewhere in the home’s main plumbing, and while you can often identify the type of blockage and fix the issue yourself, sometimes a toilet that backs up into the shower when flushed needs professional attention. 

If you find that your toilet gurgles up into the bathtub or the shower when you flush it, try the gentlest method (hot, soapy water and plunger) first before moving on to the more aggressive methods mentioned above. If all else fails, don’t hesitate to call on a reputable plumber in your area to fix the issue right away. Don’t let a toilet backing up into your shower go unchecked as it could be a sign of serious issues in your home’s plumbing system. 

You may also find this article interesting No Hot Water in Shower – But The Sinks Are Okay?

Plumber and HVAC Technician | Website | + posts

As a retired Master Plumber Jamie has over 30 years of hands-on experience, making his plumbing knowledge second to none. He has also worked on both residential and commercial HVAC installation and repair projects.