Waste comes back to the bowl after flushing: reasons and solutions

When you wake up in the morning, you must go to the washroom. But what if the flush system is not working perfectly? Sometimes the toilet bowl remains unclear after a flush, and the garbage returns to the last place. This is not problematic but also disgusting. You must know how to fix it if you want to save some money and time. In this article, you can learn the reason for this issue and how to solve this.

Flushing process of the toilet:

The flushing system is the leading cleaning process of the bathroom. This process is also known as pre-commissioning activity. Pimping water is commonly used to clean the waste from the toilet bowl. Water from the supply pipe is stored in the toilet’s tank and uses force after you switch the flush button. This water force mainly pushes all dirt from the bowl to the septic system. If there is any problem with this process, the waste returns to the bowl. So it would help if you fixed this as soon as possible. Without solving it, you can’t use the toilet.

Why does the toilet waste return after flushing?

There are many reasons for this situation. If you want to eliminate this problem, you must find where the disturbance is happening, and then you can quickly fix it. First, look at the reason which is behind this type of issue:

Damaged cast iron or terracotta pipe:

If you live in an old home and its pipeline is also made with cast iron or terracotta, you can easily fall into this situation. Cast iron is a strong material but rusts and corrodes over its line with time. On the other hand, terracotta is easy to damage. That also interrupts waste from reaching the septic tank. That’s why it returned to last place.Damaged toilet cast iron pipe

Shifting soil:

If the soil over the pipeline shifts and causes sudden pressure into your sewer line. It may crack, leak, or collapse because of this issue, and waste can sometimes pass the drainage system and remain in the bowl. This shift results from heavy rain, sudden drought, cold temperature, etc.

Tree roots:

Tree roots also create problematic situations for the sewer pipe. If your backyard has a lot of trees, there is a chance that the roost will crack the line and leak it. The root needs water; when it gets from the drainage system, it just attaches tightly. This power not only interrupts the line, but sometimes it breaks this system. Then only water can pass some time, and the waste is stuck there. Then it gets back to the bowl after some time. tree roots in pipes who is responsible

Drain cleaner:

Yes, sometimes your drain cleaner is the reason behind the waste returning to the bowl. Suppose you don’t know that this cleaner contains sulfuric acid. This acid can ruin the metal. When you use this to clean the toilet cast iron pipe, you damage the metal. And then you must face the consequences like waste returning to its old place after using a flush.


People often put grease-type materials directly into the toilet, like oil, fat, etc. These are quickly hard when it comes to cold weather. That’s the time it dries and sticks to the pipeline. Then it clogs in there. After blocking, you know the result. So stop doing this thing, please.

Throwing flushable wipes:

I know it’s called flushable, but believe it, it’s not. These wipes can create clogs in the drainage system. Suppose you notice that these wipes are made for absorbing water into it, not dissolving in there. So it can easily flush, but after that, it gets stuck in the drainage system. Then you face an issue like this.

Fault in  P or S trap:

The S or p-shaped pipe you must notice on the back side of the toilet bowl rises from the ground. The S tarp is mainly used to prevent foul odor after using the toilet to come to the washroom. On the other hand, P-trap also works in these circumstances. Their shape is different, but their function is the same. But when any change clogs this trap, the waste comes back after you flush it. If those traps are not entirely blocked, you may not face this issue at first.

How to Unclog a Vent PipeClog in plumbing vent:

The plumbing vent is not only used to carry water but is also used to remove toxic gas from the washroom and allow fresh air in there. This also creates pressure in the line and increases the power of flushing. By any chance, if the vent system gets clogged or shut, then the pressure also decreases. That also creates this kind of issue then. Because for a successful flush, you need a maximum rate of power of force. 

Insufficient flushing flow:

Low-flush toilets remain suitable for a decade. This type of toilet is very well known for saving water and reducing utility charges. But after using this for many years, you need to upgrade or replace it. Because this toilet is very easily clogged, the water force is insufficient. The toilet paper and waste can’t entirely push down the septic system through the S or P  trap. Some of them get stuck in there and return to their old place. 

These are the main reasons for returning waste to the toilet bowl. If you find the reason correctly, you can also solve this.

The easy fix: the toilet flushes, but the waste comes back again

We talk about every possible reason behind the waste returning situation in the toilet. But you need to know how you solve this. If you examine the exact fault, you also fix it yourself. Let’s see how to solve this issue:

If your bathroom is old or you have used it for a long time, you must face this issue often. Old-version toilets are not designed for long, and old drainage systems are built with terracotta or cast iron pipe. These are susceptible pipelines and can easily damage. So you need to replace the toilet and install an upgraded one. You can fix this issue, but someday, you will face this kind of issue again and again. So if you have this kind of issue repeatedly, change the old toilet and get a new one.

  • Home remedy:

This occurrence happens if there is any clog in the pipeline. To unclog the toilet, you can follow some home remedies like baking soda and vinegar. These are the perfect unclogging agent in the house. And from the internet, I think you must know how to use this solution to clean your toilet.

You also follow the second-best method to unclog the toilet with the help of a plunger. Every house has this in its washroom. If you don’t think the pipeline doesn’t block totally, you can also use this plunger there to clean it. 

If anything is stuck in the trap way, you can’t remove it using a plunger, so you need to use the sewer snake or auger. Many plungers are used to unclog the toilet. And if you have this, you also can use this. This is a beneficial solution if you accidentally flush any big thing into the bathroom. You can easily pick this with the help of these two things from the bowl or S-trap.


This situation is prevalent when you use the toilet every day. If you don’t want to face this issue, clean the bathroom regularly. And if you live in an old house, the drainage system is also old. Repairing this type of toilet is tricky; you can’t find the equipment in the market quickly. So change the old one and install an updated one. I think this can quickly solve this kind of issue. Solving the problem yourself can save money, but if you cannot find the exact point, call a plumber to help you out.

Hi, this is Robert Crossan, the owner of this website, has 17 years of experience in the installation, maintenance, and repair of toilets and plumbing systems. After completing the Level 2 Basic Plumbing course in 2005, I started working in both domestic and commercial buildings as a professional plumber. So I can figure out the core difference between different toilet models and brands. It also helped me monitor their work performance and setbacks.

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