Q&A / 

Clogged Toilet

DEAR TIM: Every now and then I have to deal with a clogged toilet. But lately the blocked toilet seems to be happening with greater frequency. Could there be a problem with the toilet itself or a clogged drain? What can I do to troubleshoot the cause of the problem? Is it possible for me to damage the bowl while clearing a clogged toilet? What do you do when faced with this unpleasant task? Harmony T., Sandusky, OH

DEAR HARMONY: You'd be surprised how many folks are stymied by this common problem. Clearing a clogged toilet happens all over the world each day. While traveling, you could even come across a blocked toilet in London! I've dealt with my fair share of toilets that don't want to drain, and have found that a vast majority of the problems can be traced to either too much toilet paper being used or, in some rare cases, poor design of the toilet bowl.

This plunger and a 5-gallon bucket are usually all you need to fix a clogged toilet. PHOTO CREDIT:  Tim Carter


You probably have never seen what the underside of a toilet looks like or seen the piping system that connects to a common residential toilet. If you did, you'd probably shake your head wondering how they don't get clogged more often.

Toilet bowls are configured with a drain pathway that's called a colon. The convoluted pathway inside a toilet bowl looks not much different than a curvy road rally course with one or more hairpin turns or your own intestines! This pathway inside the toilet bowl helps create the water seal keeping sewer gas and vermin from entering your bathroom.

The diameter of this colon is usually over 2 inches, and it connects to a 3-inch drain pipe in the floor. In some houses, the drain line may even be a 4-inch pipe. If waste and paper can make it through the colon in the toilet, you can see that the larger drain pipe in the floor can easily accommodate the waste from the toilet. This is why a clogged drain line is almost never the problem.

To test to see if your drain line or colon is clogged or partially clogged, first make sure the toilet is flushing normally. If you see the water swirl around the bowl and disappear with that classic slurping noise, you're ready to begin the test. Fill a 5-gallon bucket with water and pour it into the toilet bowl as fast as you possibly can. I mean quickly!

If the toilet bowl does not overflow, this means that the toilet colon and the drain line are wide open. There may be a plastic army man wedged in the colon allowing the water to pass, but let's assume you don't have these toys around your home.

If the water from the bucket drains rapidly, you could still have a design problem with the toilet. I've seen discount toilets that have a very tight turn at the end of the colon where it connects to the drain pipes at the floor. Solid waste and toilet paper can have a tough time passing through this very tight turn. High-quality name brand toilets don't have this design flaw.

You can damage a toilet if you use the wrong tools while fixing a clogged toilet. I would only use a plunger and a bucket of water. That's all I've ever used in all the years of working on toilets. The clogged drain snakes made from flexible metal can scratch the polished china surface of your toilet if you get too aggressive.

As crazy as this sounds, water alone can often fix a clogged toilet without a plunger. You may have noticed in the past that when a toilet clogs, the toilet bowl fills with water from the tank but doesn't overflow. But when you come back minutes later to look at it, the water level in the bowl has mysteriously fallen.

This happens because water from the bowl is seeping by the clog. If you wait for the water level in the toilet bowl to drop on its own and then pour a bucket of clear water into the toilet as fast as you can making sure it doesn't splash out or overflow the rim of the bowl, you'll be shocked to discover most clogs are dislodged by this rush of water.

I only use a plunger when several buckets full of clear water don't do the trick. Be sure the toilet bowl has more water in it than the normal level of water when using the plunger. The weight of the water, in addition to the action of the plunger, is what helps to clear the clog.

You don't want to use a plunger when the water in the toilet bowl is almost overflowing the rim of the bowl. You'll have a real mess on your hands. Remember that water is heavy and it's weight alone can persuade a mass of toilet paper and solid waste to pass through the toilet colon.

Mineral deposits that collect around the syphon jet hole in the bottom of the toilet bowl can also cause the problem. The water from the toilet tank needs to enter the toilet bowl rapidly to force waste through the toilet into the drain pipe. A partially clogged syphon jet hole or a flapper valve that's closing too rapidly not allowing all the water from the tank to enter the bowl can make you think the toilet is clogged when it's not.

The bucket-of-water test can clear clogs caused by this. If the syphon jet hole is partially clogged, muriatic acid will often dissolve the deposits.

If you decide to try muriatic acid, make sure the clog is gone and clear water is in the bowl. Pour a bucket of water rapidly into the toilet bowl to lower the water level in the bowl. Then add 12 ounces of muriatic acid to the water in the bowl. Allow it to sit in the toilet for several hours.

Be sure to wear goggles and old clothes as you do this. Pour the acid into the toilet slowly to minimize splashing. Open the bathroom window to ventilate the harmful fumes. Put the toilet lid down so that animals can't get into the harmful brew.

After waiting several hours, and wearing rubber gloves, carefully use a small wooden stick to gently scrape the opening of the syphon jet hole. Do not use any metal to do this.

Before you flush the toilet, it's a good idea to neutralize the acid. You can use a cup of baking soda to achieve this goal. Add it slowly to the liquid solution in the bottom of the bowl and stir it with a paint-stirring stick.

Now it's time to flush the toilet to see if the acid did its job. You should see a significant difference in the flushing action if the syphon jet hole was clogged with deposits. The acid will not hurt the toilet bowl or the plumbing drain pipes.

Column 855


8 Responses to Clogged Toilet

  1. I once had a toilet that would not flush reliable and after many failed attempts to fix the problem I decided to remove the toilet to take outside to do a thorough acid wash. However, when I removed the tank I realized the problem. The PVC fitting at the bottom of the tank was too long and hung down too far below the tank. This only left about a 1/8 inch space between the bottom of the PVC fitting and the flat area where the water enters the lower unit. By cutting off about 3/4 inch of the PVC fitting this allowed the water from the tank to flow into the bowl fast enough to reliable flush.

  2. My toilet WILL flush ONLY if I precede the flush with a shot of dish washing detergent. In my area they want almost $350 to remove the toilet, no guarantee if they break it, so i endure the inconvenience, HELP PLEASE, any thoughts ?

    • I suggest you do what I say in this column. Check the syphon jet hole for hard-water lime and the holes under the rim of the toilet. Did you do the 5-gallon-bucket test? If the toilet takes the water as fast as you can dump it, it's an issue with the water from the tank not getting into the bowl fast enough.

  3. I've try everything and nothing it's still clogged my husband took the toilet out and pour water n we could see it in the curb what else can we do an expert came and couldn't unclog it please help

  4. My toilet has been clogged for over a month and since I'm on a fixed income I can't afford a plumber. We've tried chemicals, plunging, buckets of hot water, all of which have not worked. We've also tried a snake but it rolls up and we can't get it to make the turn to go down the toilet. Two things I should tell you: The family member that uses that toilet is taking medications that cause extremely hard stools so we're pretty sure that has caused the clog. And right now, toilet will flush, fill up then drain very slowly. We aren't able to use the toilet for solid waste, and don't flush the toilet paper, which is inconvenient to say the least. The problem with the slow draining is that chemicals don't stay at the blockage long enough to loosen it. Anything you can suggest will be appreciated. Thank you.

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