How Does A Toilet Work?

You probably use the toilet in your home several times a day. You may not, however, give much thought to how the toilet functions. When your commode is working perfectly, that’s not a problem. If something breaks, however, it’s useful to have a good understanding of how the toilet does its job so you can troubleshoot a fix. Fortunately, commodes are not complicated machines. Anyone can easily understand the basic workings of their home toilet. So, how does a toilet work?

Understand the Design

Toilets haven’t changed much since their introduction. Whether you have a low-flow commode or a standard variety, the design is essentially the same. As timeless marvels of human invention, toilets require gravity and siphons to work properly. When the valves open and close, water follows the laws of physics as it moves through the toilet, flushing away waste and supplying clean water.

With a glance, you notice four key components to your toilet. The tank is the large box that sits next to the wall. On it, usually off to one side or the other, is the handle you push to flush. The bowl is where the waste is collected and flushed clean, while the seat is the flat area above it where you sit. Meanwhile, inside the tank, waits a few more mobile components that allow it all to function predictably.

Push the Handle

The first thing you do after using the toilet is press the handle. On most models, the handle is located on the side of the tank, while some newer toilets are automatic with sensors that require no handles at all. It doesn’t take much effort to activate the flush, but you usually must wait a few seconds between flushes before pushing the handle down again. There’s a reason for the delay, as when you push down on the lever, you begin a chain reaction inside the toilet’s tank.  

Yank the Chain

The handle, of course, is on the outside of the tank. On the inside, the toilet handle is attached to a flush chain which activates the flush valve. The flush valve is a component that controls how much water moves from the tank into the bowl. Made from rubber or flexible plastic, the flush valve is often called the flapper. When the chain lifts the flapper, gravity moves approximately two gallons of water from the tank into the bowl. When all the water has moved from the tank into the bowl, the flapper returns to its resting position in the flush valve. By sitting flat on the bottom of the tank, the valve prohibits water from flowing from the tank into the bowl. This, of course, allows the tank to refill with water for the next time you need to flush your toilet.

A broken, damaged, or ineffective flush valve is the most common toilet problem. Often called a silent leak, a bad flapper can cost a fortune in high water bills. If you notice a trickling sound after you have flushed the toilet, you may need to replace your flush valve. Periodically inspect the flapper to be sure it isn’t allowing water to leak from the tank into the bowl when you don’t want it to.

Watch It All Go Down the Drain

As the flush valve allows water to pass into the bowl, the weight of the water and the pull of gravity encourage waste water to flow out of the tank through a drain into your home’s sewage system. Essentially, the simplistic brilliance of this invention is that your toilet creates a siphon that effectively removes waste. When all the waste water is gone, there should be only clean water pooled in the bowl until you flush it again.

You probably know that clogs can destroy a toilet’s siphoning power. If something refuses to pass through your toilet bowl into the sewer drain, it may make flushing your toilet impossible. Continuing to try, of course, can lead to a messy overflow of the bowl, as you can’t send clean water from the tank into the bowl if waste water isn’t successfully exiting the bowl. Accordingly, you must clear drain clogs using a plunger or snake to restore your toilet’s siphoning ability, and preferably quickly.

Hear the Tank Fill

After flushing, you will hear water flow back into your toilet’s tank. The tank on your commode sits full until you need clean water to flush the toilet. Part of the hidden components in the tank is the fill valve, which responds to an empty tank by filling it again. When the flapper closes, the fill valve releases water into the tank to fill it up to the designated level necessary to flush the toilet when it is needed.

As you may suspect, however, your tank cannot be allowed to fill with too much water. If it does, you may have a damaging overflow. To control fill, the fill valve is connected to a float which sits on top of the water in your toilet’s tank. When you flush, the ball float drops as the water level drops, setting off a refill process. As water flows into the tank, the ball begins to float back up to the tank’s necessary water level. When it reaches level, the position switches off the fill valve to stop pumping water into the tank.

If your toilet’s float malfunctions, the fill valve may not know when to stop allowing water to flow into the tank. It also may stop prematurely, giving your toilet insufficient water to flush. As such, if you have too much or not enough water, check your float. Often replacing the float fixes flow problems.

Watch the Bowl

The bowl, like the tank, will also fill once the flapper closes. This is done via the refill tube, which is a small rubber tube that connects to the fill valve and empties into the overflow tube. This piece sits in the tank and connects directly to the bowl. The water from the refill tube is pulled down to go around the inside rim of the bowl and trickle down to help clear any waste residue from the inside of the bowl, as well as refill the bowl for the next time it is used. The bowl should be kept moist because a dry environment will retain waste, as well as dry and crack the interior finish.

With all of these parts working together, the toilet is kept ready for use whenever it is needed, as one of the most well-used, reliable fixtures in the home.

Be Sure It Doesn’t Overflow

As you probably suspect, with gallons of water moving around in the toilet, floods can happen. To keep water from flowing where you don’t want it, your toilet has some failsafe components. The most significant one is the overflow tube. If the tank receives too much water from the supply, the water flows through the overflow tube and into the bowl. From there, it moves into your sewer drain through the same function as a regular flush. Of course, if water is flowing into the tank too quickly, the overflow tube may become overwhelmed.

It’s also worth noting that your toilet bowl does not have an overflow failsafe. Since the sewer drain is the only way for water to exit the bowl, you must be sure the drain is clear. If you have a clog or other blockage, remove it to avoid a damaging flood.

As a savvy homeowner, you want everything in your home to work its best. When it comes to your bathroom, you must keep your toilet in tip-top shape. By understanding the basic parts and processes of toilets, you can better diagnose and fix any problems that occur with your home commode.