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Toilet Flushes But Waste Comes Back: Possible Reasons Why

Plumbing systems are a modern luxury that most of us take for granted. That is until something breaks!

Toilet flushes but waste comes back, why is this happening? The answer is more simple than you think. Sometimes, the problem is with your toilet itself, but usually, the issue is your sewer pipes.

By the end of this article, you’ll know why your sewer pipes are broken, how to clear a clog, and how to fix a broken sewer pipe.

Common Reasons Why Your Toilet Backs Up

When a toilet backs up, it is usually due to an issue with the pipes. Broken or clogged pipes are the most common reasons why toilets back up. As you flush the waste down the toilet down to faulty pipes, it has no place to go. The waste finds an exit by coming back up to your toilet.

As if this wasn’t unpleasant enough, there are times when the waste will back up into your bathtub or shower. When this happens, it is your toilet that is causing the waste to come back.

If your toilet flushes but waste comes back, don’t worry! There is an explanation after you do some investigating. Let’s explore common reasons why your toilet is backing up.

Toilet Flushes But Waste Comes Back

Obstructing Items Can Cause Blockage

Pipes can become clogged if an object was flushed down the toilet. This is common in homes with children. Kids tend to be playful in some of the most inappropriate places. Check to see if one of your children flushed down a toy or other item.

The toilet cannot handle strange objects. If a toy gets lodged in the pipes, it can cause your toilet to back up.

Flushable Wipes Can Still Clog Your Pipes

You would think that when a product has the word “flushable” on the label it means it. Unfortunately, it isn’t so for flushable wipes. One thing is for your toilet to be able to flush the wipes. But this doesn’t mean that your pipes can handle them and drain them fully.

Sewer pipes are not designed to handle solid waste. Feces and toilet paper break up after it is flushed. Flushable wipes don’t break apart after they are flushed. They remain intact and can cause blockage.

If you want to enjoy a working toilet, you must certainly throw away flushable wipes in the garbage bin.

Sulfuric Acid Found in Drain Cleaners Eats Away Metal Pipes

Drain cleaners are supposed to unclog and clean pipes. However, it is very strange that most of them are sulfuric acid ( It is a harsh chemical that eats away at metal pipes. If you’re scratching your head, you’re not the only one!

If your property has cast iron pipes, stay away from sulfuric acid. Perhaps you can find a drain cleaner that has ingredients that don’t ruin metals. Using drain cleaners will certainly unclog your toilet, but eventually, you’ll create an even bigger problem. Not to mention a more expensive one!

Rusty Metal Pipe

Shifting Soil Can Break Pipes

It is natural for the soil under your property to shift. However, when this occurs, it causes the ground to expand. This causes pressure which may lead to damage to sewer pipes.

Shifting soil has enough force to cause cracks, create leaks, and even collapse the pipes. What causes soil to shift? There are many reasons why soil shifts. Freezing temperatures, rain, or drought can all cause this phenomenon.

This is a tough scenario because there’s not much you can do against Mother Nature. As they say: “Nature will take its course.”

Trees Have Strong Roots that Damage Pipes

Along with shifting soil, Mother Nature has also designed strong solid trees with powerful roots. Having a property surrounded by trees creates a beautiful scenic environment. However, tree roots can be a problem for your plumbing.

Trees have hundreds of roots that break through concrete! As the roots expand to search for hydration, they run over anything on their way. They can crack pipes and cause your toilet to eventually back up.

Also, sometimes there is an existing leak in one of your pipes. Since water leaks out of the pipe, the tree root is attracted to it. The root attaches to the pipe and uses the crack as an access point to a water source. Once this happens, the pipe can clog or it can break.

Sounds like a science fiction movie? It sure does! Nature’s force is unparalleled. You would have to chop down trees to avoid this problem, but that’s a tough decision.

Pipes Made From Cast Iron Are Outdated

Cast iron pipes are becoming a thing of the past. Homes that were built before the 1970s commonly used cast iron. This type of metal corrodes and rusts as time passes. The corroded and rusty cast iron pipes cause more issues than just clogging your toilet.

They can also cause water and structural damage. Plus, the corroded pipes allow sewer gases to escape into your home. Besides invading your environment with a foul odor, this problem also threatens your health.

Terracotta Pipes Have a Weak Structure

You probably didn’t think that terracotta pipes still exist. They are ancient, dating back to 4,000 BC. For a strange reason, some builders still use this material. These types of pipes were common during the early 1900s. The low price and vast availability made them popular.

Although they have been used for thousands of years, they are weak. They easily crack and create leaks. It is best to stay away from terracotta when planning your plumbing structure.

Grease is a Plumbing Nightmare!

Grease, oil, and fats may seem harmless. However, they create a huge problem that not only affects your property but also the environment. In addition, grease can create structural problems on a global scale.

According to industry experts, grease in pipes ( is the number one reason why clogging occurs. If your toilet is backing up, it may be due to the oil or grease you have flushed down (see our post on the damaging effect of flushing oil down the toilet for more information).

Grease is a Plumbing

The problem with grease is that it solidifies. Even if you pour hot water down a drain along with the grease, it still eventually becomes solid. The accumulated grease becomes a type of “gunk” that thickens and mixes with solid materials that create a huge fatberg.

What is a fatberg ( Now, that is something you would certainly see in a science fiction movie!

A fatberg is a glob that forms from grease and solid materials in the sewage system. It can become bigger and bigger until it creates monumental damage. The problem is costly and requires the government and utility companies to fix it.

If you want to see a fatberg for yourself, the Museum of London ( has one on display that measures 820 feet!

What is the Solution?

If your toilet is backing up, hopefully, it’s due to a simple clog. If this is the case, you can try DIY solutions such as these:

  • Vinegar and baking soda
  • Dish soap
  • Hot water
  • Coat hanger
  • Cream of tartar
  • Borax
  • Lemon juice
  • Salt

This video shows you an easy way to unclog a toilet:

If these compounds don’t do the trick you can use a plunger for superficial clogs. If the clog is deeper down the drain, a sewer snake can be used. It is a simple tool you can purchase online. Check to see which size is appropriate for your pipes.

You can also call a plumber if you feel the solution is out of your scope of expertise. A licensed professional will also have access to other methods such as hydro-jetting. This pipe cleaning technique cleans your pipes with high pressure. It’s even strong enough to remove tree roots.

There you have it! Now, you have a better idea of why your toilet flushes but waste comes back. With a careful inspection, you’ll be able to take the necessary steps to get your toilet up and running again. Happy flushing!

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