Why is My Toilet Overflowing but Not Clogged?

Why is your toilet overflowing but not clogged?  There could be a few reasons why this is happening. 

Let’s explore why and find some fast solutions. 

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Toilet Overflowing but Not Clogged: What to do?

Can a toilet overflow without being clogged? You bet. Why would a toilet overflow on its own? Check out the reasons and solutions below.

Why is My Toilet Overflowing for no Reason?

Can a toilet overflow for no reason? The answer is no. There are 6 main reasons why a toilet can overflow without being clogged in a way that is easy to remove.  As always, the best toilet auger is the best tool to deal with a shallow or deep toilet clog.  Why is my toilet overflowing for no reason? 

  1. Vent pipe might be clogged 
  1. It IS clogged 
  1. Clog is past the P Trap 
  1. Septic Tank is Full or Malfunctioning 
  1. Waste Line Venting Issues 
  1. Float Needs Adjusting 

Toilet Overflowing but not Clogged: Toilet Overflowing for no Reason 

Why is your toilet overflowing for no reason?  That’s because there IS a reason, but it’s not as obvious as a shallow clog that can be plunged out of your toilet.  You will have to do some deeper investigation to see which one of the 6 options 

Toilet Overflowing for No Reason: Our 6 solutions 

Here are the 6 solution if your toilet is overflowing and a plunger isn’t working. 

Vent Pipe Might be Clogged

A plumbing vent lets air into your pipes to help regulate air pressure and make sure that waste is moving through your pipes properly.  This long pipe is called a plumbing vent, sewer vent, plumbing stack vent, or roof vent.  They also work to vent any sewer gases and nasty odors straight out of your roof through a long pipe.  If your pipes are starving for air, they can’t remove waste water and fumes.  Take a look at our post about unclogging your vent pipes HERE.

Your Toilet IS Clogged

Your best bet before going nuclear and thinking this is a super serious problem, is to use a toilet auger to really get into the pipe and clear it out.

Clog is Past the P Trap

A clog past the P Trap won’t usually be solved with a plunger or a hanger. A toilet auger is from 3 to 6 feet long and should get the clog out. If the clog is deeper than this, you will have to hire someone that has a commercial auger and the know how to solve a complicated clog.

Septic Tan is Full or Malfunctioning

Our best advice is to call in a septic tank specialist and/or a septic company to pump your septic ASAP.

Waste Line Venting Issues

If you are having waste line venting issues, you may not have enough vents or proper vents installed. Or, you may need to unclog your vent pipe from your roof. Read this post to figure it out.

Float Needs Adjusting

Sometimes the float that regulates how much you tank fills with water may need to be adjusted. Adjusting the float is as simple as bending the metal that holds the float downwards. This means that the tank will stops filling sooner.

What is a Toilet Float?

Red Arrow Pointing at the Toilet Ball Float Source: Family Handyman

A toilet float is a mechanism inside your toilet that determines how much water should be in your tank. When you flush the toilet, the flapper opens allowing water out, and the float sinks inside the tank.

When the tank starts to fill up, the float lifts up and once it reaches the proper fill level, the filling valve will shut down. The float makes sure that your tank doesn’t overflow with water.

There are two types of floats: a ball or a cup float. Most toilets I’ve seen have a ball float, which is basically a big ball on the end of a metal rod that rises and falls with the water level.

Toilet Keeps Clogging and Overflowing 

If you can’t stop your toilet overflowing when flushed no matter what you try, it’s time to call in the experts. Give your local plumbing company a call. Ask your neighbors for a reference.

Can a Bad Flapper Cause a Toilet to Overflow? 

The flapper in your toilet is a piece of rubber that lifts up when you flush, allowing the water in the tank to flush your toilet and escape down the drain. A bad flapper won’t cause your toilet to overflow because it lets water out of your toilet. But, a bad flapper might be the cause of your toilet running. Or, it may cause you to be unable to flush your toilet. You can buy flappers and replace them yourself super easy. Here is a how to video on getting that done yourself.

Why does my Toilet Overflow then slowly drain?

Either you have a clog or the flapper inside your toilet isn’t working to let the water out of your toilet. Open up the top of your toilet tank and make sure the flapper and float are attached and in good working order. Then, flush your toilet and check that the flapper is opening up all the way. If not, you need a new flapper.

If those parts are working properly, then you have a partial clog in your toilet drain.

What Plunger do I Use for Which Clogs?

SinkSink Drains

Toilet Clog Prevention

Here are some tips to prevent future toilet clogs:

  • Don’t flush too much TP down the toilet at once
  • Flush multiple times during a big poop
  • Watch that the kids don’t flush anything
  • Don’t flush any wipes down the toilet. It doesn’t matter if they say they are “flushable”. They aren’t. Most of my service calls are for this issue.
  • Clean out your pipes twice per year with a toilet auger
  • Don’t flush cat litter: it turns into cement in your pipes
  • Don’t flush paper towel
  • Don’t flush large feminine hygiene products
  • Grease should be poured into a container and thrown out, not down your toilet

Cost of Hiring a Plumber Versus Buying a Toilet Auger

Hiring a plumber to unclog your toilet costs anywhere from $100- 250, depending on the area and how complicated the clog is. A toilet auger can be as cheap as $30. You can also use your toilet auger as many times as you like, so I consider it an investment.


Your toilet overflowing but not clogged can be a result of a few different things and we hope that you can solve your problem using the knowledge above.


Can a toilet overflow without being clogged?

No, the water is overflowing because it has no place to go when the pipes are clogged. You will need to unclog your toilet, try a plunger first, then a toilet auger.

My toilet is overflowing and a plunger is not working.

Make sure that you have a good seal between the plunger and the toilet bowl and try a few more times. If this isn’t working, then your clog is too deep and complicated to solve with a plunger. You need to buy a toilet auger or call in a pro.