Learn the basics so you can fix it yourself—and save!
Ever Wondered How a Toilet Works? Follow Us Into the Tank for a Closer Look!
Updated on Oct. 01, 2024
Possibly the most used household fixture, and one we usually take for granted, the toilet is a marvel of engineering simplicity. Even typical modern toilets still employ just a couple basic mechanical components. The rest of the flush relies on the natural forces of gravity and siphoning action.
But sooner or later, every toilet develops problems like weak flushing, clogs or constant running. When that happens, most homeowners just live with the problem or pay a plumber a lot for a simple fix. You don’t have to. If you know how a toilet works, you can diagnose and solve problems yourself, often in just a few minutes. So let’s lift the lid to see the magic that happens in the bowels of this underappreciated fixture.
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The Flush Handle Lifts the Flapper
The flush handle is pressed, lifting the flapper, setting in motion about 10 seconds of flushing genius.
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Water Rushes to the Bowl
The lifted flapper releases tank water into the bowl via rim jets and the larger siphon jet. The float drops as the tank empties, opening the fill valve, and the flapper drops back onto its seat.
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Gravity Happens
The bowl fills, and gravity forces water into the trapway, causing it to overflow the top of the trapway.
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Water and Waste are Siphoned Out
Water rushing over the top of the trapway creates suction, evacuating the waste and water from the bowl. As the water is pulled from the bowl, air enters the trapway, ending the siphon effect and also the flush.
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The Refill
Water rushes back into the tank via the fill valve, which is connected to the water supply line. The refill tube sends water down the overflow tube to the bowl.
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Ready for Next Time
As the tank water rises, it lifts the float until it shuts off the fill valve. The water in the bowl and the water in the trapway reach a common level, just below the top of the trapway. Check out our best toilet buying tips here.
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What’s Inside the Toilet Tank
The mechanical parts work in harmony with the natural forces of gravity and siphoning in the bowl and trap to create that familiar, satisfying sound of a complete flush.
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Most Common Toilet Problems
Now that you’ve graduated from Toilet 101 with a basic understanding of how this beautifully simple household appliance works, you’re ready to tackle toilet problems that will occasionally occur.
- Clogged toilet: From time to time toilets get backed up from trying to push more material down the trap than it can handle. Not to worry! It’s an easy fix, usually. There are many ways to unclog a toilet, but the best, most common one is to use a plunger.
- Running toilet: It takes half a minute or so for the tank and bowl to refill after you flush, but if it just keeps going and going, there’s probably an issue in the tank. To fix a running toilet, you might just need to adjust the float. If that’s not it, you may need to replace the fill valve or the flapper.
- Wobbly toilet: When you sit on your throne, it shouldn’t move. But if it does, you can easily fix a wobbly toilet. The most common culprit is loose bolts anchoring it to the floor, in which case, you just need to tighten them. If that doesn’t do it, you may need to shim the toilet or, in the worst case scenario, remove it and replace the wax seal.
- Bubbling toilet: If your toilet is bubbling at random or the water level rising and falling inexplicably, it might be a problem with the venting system or a clog in the drain line. This can be a little more complex problem that may require some professional help.
- Slow flush: If your toilet is a little sluggish when flushed, it might just be that the water jets under the rim need to be cleaned.
- Toilet won’t flush: There are several potential reasons your toilet won’t flush. It could be as simple as a clog or the chain attached to the handle needs to be adjusted. Problems with one or more of the various parts in the tank are also included in the list of likely suspects. Don’t panic. It’s usually an easy problem to fix.
- Broken flush handle: It could just be the that the chain connecting the handle to the flapper has come loose or disconnected. Handles can also get corroded, which can result in it not working. There are several potential fixes for a broken handle, and if you have to replace it, that’s a easy DIY task too.
- Condensation on the tank: If you live in a humid climate, condensation can form on the outside of the tank, which can drip down and make a mess or even rot out your floor. Some toilets are available with insulated tanks to prevent condensation problems.
- Loose or broken toilet seat: A loose seat may just need to have the bolts tightened, as they do come loose over time. If that doesn’t do it, or if the seat is cracked or broken, you can easily replace the toilet seat.
