Toilet plunger at work (C) Daniel FriedmanClogged Toilet Repair Guide - How to Diagnose & Repair Stopped Up Toilets

  • TOILET CLOGGED - CONTENTS: Clogged toilet repair guide: toilet overflow - repair and prevention. How to diagnose and fix a clogged toilet drain. How to fix a toilet that is overflowing when flushed - in an emergency
  • POST a QUESTION or READ FAQs about how to fix a toilet that is clogged, flushes poorly, leaks, runs etc.

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How to fix a clogged toilet:

Here we explain how to accurately determine the cause of a clogged, stopped-up toilet or slow toilet drainage.

Understanding the cause of a blocked toilet helps assure that the right repair is made at the lowest cost.

Here we explain how to diagnose and repair problems with toilets, leaks, flushes, odors, noises, running and wasted water.

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Toilet Flushes Slowly or Backs Up - How do I Fix a Clogged Toilet or Sewer Drain?

Plumbing drains (C) Carson Dunlop Associates

All modern toilets receive human waste, urine, feces, and are intended to dispose of that matter in a sanitary fashion.

[Click to enlarge any image]

Before launching into our series of articles on diagnosing and repairing toilet problems such as clogged toilets, toilets that don't flush properly, running or leaky or noisy toilets, toilet odors, and loose toilets, take a look at the simple connection between a typical reservoir-tank toilet and the soil stack (waste piping) in the Carson Dunlop Associates sketch (above left), and review our description of basic types of toilets

If your toilet is backing up, here we give some advice on how to proceed. For added details on alternative methods to un-clog a blocked drain, also see BLOCKED DRAIN REPAIR METHODS for details of methods used to un-block a clogged drain line.

If you have had sewage back up and spill out of toilets into the building, cleanup is needed and you may face bacterial hazards. See SEWAGE CONTAMINATION IN buildings for advice.

Chase Patrick Gilligan as a toddler- leads to Sewer drain clogged with childs underpants (C) Daniel Friedman

Is the sewer line or soil stack clogged?

If flushing the toilet leads to a backup, or worse, a toilet overflow, it's possible that the toilet drain pipe has clogged, or there may be a clog right at the base of the toilet itself.

Before going to work with a toilet plunger - (as shown in our photo at page top) which is normally the first thing to try, ask some questions about just when and how the clog occurred. Because if a child or pet has dropped something into the toilet, you do not want to push that blockage further into the piping system where removing it will be more trouble and more expensive.

Our grandson, learning toilet training, flushed his peed-in underpants down the toilet. We have also found child's toys, and once, a dog's bone clogging the waste line just below the toilet. It might have been possible to fish this obstruction out of the toilet drain with a wire, but ultimately the owners simply removed the toilet to retrieve the blocking underwear.

If other building drains are working fine, but one toilet is flushing poorly, it is possible that there is a local blockage close to the toilet itself.

Brian Gilligan found this drain clog by asking Chase what happened to the missing underpants. He then removed the toilet from the floor [image], and by luck, the underpants were able to be easily retrieved - unblocking the clogged toilet drain before a backup and toilet overflow catastrophe had occurred.

How to Use a Toilet Plunger to Clear a Blocked Toilet

Toilet plunger at work (C) Daniel Friedman

If no one has thrown any toys, clothes, or objects into the toilet, try using a toilet plunger. If there is sewage in the toilet you might want to wait a bit to see if the water and sewage level lowers before plunging - just to reduce unsanitary splashing.

At BLOCKED DRAIN REPAIR METHODS we discuss alternative methods used to clear a blocked drain.

Tips for Success Using a Toilet Plunger

The toilet plunger, an old stand-by, is often effective if

  • The blockage is near the fixture where you are plunging
  • The drain line is full or nearly full of water and waste (if the drain is not full - you have a slow drain not one that is totally blocked) try flushing the toilet and as the water begins to flow down the drain, immediately start using the toilet plunger.
  • You plug any sink traps, overflow openings, or vents that are close to the drain line you are plunging. This step might not be needed to clear a toilet, but it certainly is if clearing a blocked sink or tub.
  • Persist: don't give up too soon.

    We have successfully un-blocked recalcitrant clogged toilets that did not respond at first, but that began to work just fine after five minutes of plunging. Plunge! Plunge! Plunge!

Toilet backup

Watch out: don't flush a toilet if the bowl is already at a high level of water or waste - you're asking for a toilet overflow if you do.

In the unattractive example at left we show sewage backing up into the bowl of a clogged toilet. Flushing this toilet with the wastewater high in the bowl means an almost certain overflow of sewage into the bathroom. That mess wioll require both a mop-up and disinfection of the area.

Watch out: if you get toilet water on your skin, wash with soap and water. Same with clothes. Do not put a dirty finger in your eye, mouth, or in a cut - you are risking an infection.

For advice on using other methods to clear a blocked drain, including mechanical removal of an obstruction, use of drain clearing chemicals, more on using a toilet plunger, using a plumbing snake, using a kinetic water ram.


Porta potti
If you cannot immediately un-block a clogged toilet, short of going to the neighbor's to use their bathroom, you might want to use a portable or chemical toilet.

  • Call a port-a-john portable toilet company, if all else fails and you have lots of guests who will be in the building over an extended time.

    You can rent one or more portable toilets.

    In a pinch you may be able to borrow a camping toilet or chemical toilet like this Thetford porta-potty from someone who has that device.

If you have had sewage back up and spill out of toilets into the building, cleanup is needed and you may face bacterial hazards.

See SEWAGE CONTAMINATION IN buildings for advice.

Toilet with tank lid on seat(C) Daniel Friedman


At More Reading is our list of toilet trouble diagnosis and repair articles. You will see that some toilet problems are fixed easily and right at the toilet by a simple adjustment, while others may not be the toilet's fault at all, and may need more thoughtful diagnosis and repair.

Taking off the toilet tank top: Some of these simple toilet diagnosis steps require that you look into the toilet flush tank on the back of the toilet.

Just lift the top off of the toilet tank and set it carefully aside on the floor where you won't break it or trip over it.

If you leave the tank top on the toilet seat (as we did for this photo) you're asking for trouble, and also, it's a bit in the way.

Our sketch below shows the parts you'll see inside the toilet tank. You may want to refer back to this drawing while reading the details of each class if individual toilet problems listed above and how they are detected, diagnosed, and repaired.

This article series discusses the cause, diagnosis, and repair of toilet problems (water closet problems) such as a toilet that does not flush well, clogged toilets, slow-filling toilets, running toilets, loose wobbly toilets, and odors at leaky toilets.

Reader Question: all of our toilets are overflowing - they take turns, but the problem comes & goes

All three of our toilets are taking turns overflowing if we let them. Some days it's one, another day it's it's another and on and on~ All other house drains are perfect. What is the problem and how do I fix it. Thank you! - Cynthia 7/29/12


Cynthia the helpful observation in your note is that all three toilets overflow - telling us that there is a system problem, not a blockage at an individual toilet drain line.

There are some more subtle possible problems to find, but I'd start with these directions of investigation:

  • A partial blockage of the main system drain at some point between where all 3 toilets have joined a common drain line, and the ultimate connection to a sewer main or septic tank. The reason that the clog or toilet backup might be intermittent could be due to the combined usage wastewater volume.

    When you have a partial drain blockage at a distance, pretty far down in the main building drain system, you can run water or flush a toilet without backup if the drain line is sitting there empty. The wastewater rushes to the blockage, slows there, but slowly drains past the blockage. But when you are using more water at once, the drain line can fill up enough to back up into the building.

    The intermittent nature of which toilet overflows depends in this case on which was flushed last.
  • If you are connected to a private septic system, a blockage at the septic tank, piping, or failing drainfields - though usually this problem would not intermittent though it might be weather dependent (in wet weather if the drainfield is saturated the system may back up)
  • Less likely, a blocked plumbing vent system, as I think the toilet clog problem would not be intermittent in this case, though it might be weather dependent (snow covers the vent exit for example)

We discuss slow drains and clogged or failing septic systems - onsite waste disposal systems - septic tanks, drainfields, separately at SEPTIC SYSTEM INSPECT DIAGNOSE REPAIR.



Continue reading at CLOGGED DRAIN DIAGNOSIS & REPAIR or select a topic from the More Reading links shown below.

Or see TOILET FLUSHES POORLY to diagnose and fix slow-flushing toilets caused by inadequate water volume in the toilet bowl or in the toilet tank or cistern, or caused by a partly-blocked drain, defective vent

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TOILET CLOGGED at - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

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