Toilet Backing Up into Shower: What to Do Next

Water backing up into a shower
There are just some things that should be kept separate—like your toilet and your shower, for instance. A clogged toilet on its own is bad, but when your toilet is backing up into your shower, things go from bad to worse. While you may go years without being reminded, these two systems are connected, and when there’s a problem with that connection, you may see problematic effects on both.

What’s Causing Your Toilet to Back Up into Your Shower?

When you flush a toilet that is working properly, it drains through your sewer line, transporting wastewater from your home to your sewer main. But if, when you flush your toilet, water comes up through the drain in your shower, that process is obstructed.

Think of your drains like a river and its tributaries. Smaller streams (secondary sewer lines) converge and form one large river (your main sewer line). If your main sewer line becomes clogged, even partially, it can cause backups in all your smaller sewer lines, like those connected to your toilet and shower.

There could be a number of things causing your line to clog, but here’s a lineup of the most likely culprits:

  • Tree roots: Trees seek water, and your sewer line is a plentiful source of moisture, especially if there are weaknesses or leaks in the pipes. Dryer times call for drastic measures, and tree roots are smart. A tree at your neighbor’s house down the block may reach all the way to your sewer line for water! Eventually, roots can break into your sewer line, causing a clog.
  • Flushed foreign objects: Children’s toys, feminine hygiene products, thick toilet paper, or paper towels—even “flushable” wipes—can cause blockage to occur in your sewer line. The only things that should be flushed down your toilet are water, human waste, and biodegradable toilet paper. Anything more, and you might find yourself with some serious damage.
  • Hair: Though it often happens slowly, our hair falls out during bathing. It’s not a notable amount, but little by little it can become a problem, especially as it forms a net and catches other substances that would ordinarily drain properly. As hair accumulates in your drain, it can slow drainage or even stop it altogether.
  • Pipe scale: Scale is a mineral layer usually composed of calcium or magnesium that occurs naturally in our water. Scale can form on any surface that meets water, including your pipes, as these elements are left behind. This layer can build up, causing a blockage in your sewer line.
  • Grease: Fats, oils, and grease can be nasty when allowed into drainage systems. As these substances are washed off dirty dishes in the kitchen, they can travel into the same sewer line that services your bathroom. If grease builds up enough to form a clog in the main line, you may see repercussions in all the drains.
  • Other miscellaneous materials: Sometimes, it’s not just one main offender that causes a blockage in your sewer line but rather many different objects and substances. Laundry detergent, built-up soap, or other materials can form a clog that could be making your shower and toilet drains fail.

The Fix Is In: How to Stop Your Toilet from Backing Up into Your Shower

Now that you know what could be causing your toilet to back up into your shower, it’s time to find a fix. Before you reach for those gnarly chemicals promising to clear out any clog, we’ll stop you right there—it’s likely that no amount of drain cleaner will solve this problem. In fact, drain cleaner is corrosive and could make the problem worse. Instead, try these strategies to clear your sewer line of a clog:

  • Head above water: Before you do anything else, it might be a good idea to turn off your main water supply. If the clog is large enough to cause water to rise in the shower drain, you run the risk of flooding as more water fails to drain. Your main water supply shutoff is likely in your basement or garage, or near your water heater.
  • Snake it up: If you have one handy, a drain snake could unclog the line. Begin by cautiously feeding a toilet snake down the toilet, use caution with this method as you can cause permanent marking on the toilet finish. Spin the snake clockwise as you enter the drain and then counterclockwise as you carefully pull it back out. As for the shower drain, remove the screws from the drain cover and pull it off. Push the drain snake into the curving pipe below, spinning clockwise on the way in and counterclockwise on the way out. If you’re successful, you’ll find the clog itself and the snake will draw it up as you spin it out.
  • Clear the air: Occasionally, a blocked vent pipe will cause toilet water to back up into the shower. From the roof of your home, find your vent pipe. (It will probably be over your bathroom.) Using a flashlight, search for any obstructions in the pipe. If you find any blockages that are near the top of the pipe, carefully pull them out using a retrieval tool. If there’s debris further down the pipe, spray a garden hose in it or use a drain snake to push it down.
  • Call in the pros: If you’ve tried all the above to no avail, it’s time to call in the plumbing professionals at Mr. Rooter® Plumbing. Our team will assess the situation and determine the best solution. No matter the cause—from tree roots to pipe scale—our trained plumbing professionals have the technology and the expertise to get the job done.

When your toilet is backing up into the shower, it might seem like you’re in both hell and high water. But understanding the causes of drain blockages will help you do your best to prevent them in the future. You can rest assured, though, that when a plumbing emergency happens, Mr. Rooter is just one call away. With our 24/7 emergency service, we will be ready to take your call at any time—day or night.

This blog is made available by Mr. Rooter LLC, for educational purposes only to give the reader general information and a general understanding of the specific subject above. The blog should not be used as a substitute for a licensed plumbing professional in your state or region. Check with city and state laws before performing any household project.