The More You Know: How Does a Toilet Work?

The concept of flush toilets has been around for thousands of years. However, this fixture that we tend to take for granted has only been widely used since the turn of the last century. You may have asked yourself: how does a toilet work?

If you are a homeowner, landlord, or property manager, a basic knowledge of how toilets function lets you fix small problems on your own. And if you need to call Sanitary Plumbing for assistance, you can better describe the issue. Then, we can bring the right parts and know what to expect.

Read on for a description of how toilets operate. It will help to have a diagram of a toilet handy as you read. Also, lift the lid on your toilet tank and watch the flush cycle for a better understanding of the moving parts.

How Does a Toilet Work? A Step-By-Step Explanation

The flush handle activates the flapper

The flush process starts when you press the handle on the outside of the tank. This lifts the flapper, which is the rubber seal at the bottom of the tank. The flapper separates the tank from the bowl.

Water then flows from the tank into the bowl. Usually, the flow is from both the large siphon jet near the bottom of the bowl and the multiple rim jets around the top of the bowl.

Gravity assists with flushing

Next, gravity steps in to help with the process. Water is forced into the trapway leading out of the bowl, and this carries waste from the bowl through the trapway into the main, where it can be expelled from the building.

A siphon effect is created when this happens. Simultaneously with the rush of water, the flapper returns to its seat at the bottom of the tank once the tank has emptied completely. The resulting suction hastens the removal of water and waste away from the trapway.

You may have noticed the effect of gravity in a toilet without even activating the flush mechanism. If you dump a bucket of mop water into the bowl to dispose of it, for example, you’ll create the same gravity-assisted emptying of the bowl that occurs with a flush.

The tank refills

The closing of the flapper once the tank has emptied starts the refill process. Water enters the tank via the fill valve, which is connected to your water supply. The refill tube sends a bit of that water down into the bowl via the adjacent overflow tube, resulting in a small amount of fresh water in the bottom of the bowl for the next use.

A float in the tank rises as water refills the tank. When it reaches a certain level, it shuts off the fill valve, and water stops entering the tank. The flush cycle is complete, and the fixture is ready for the next flush.

Pro Tips for Common Toilet Problems

The toilet keeps running

A running toilet is not just a nuisance; it can result in a high water bill and cost you money. Here are a couple of common causes and solutions:

• Flapper problem: this is the most common cause of a running toilet. Either the valve is old and cracked or inflexible, or the chain connecting the handle to the valve is caught underneath it, preventing a tight seal.
• Float arm is set too low: if you have this type of float system, raise the float arm with your finger. If that stops the running, you’ve found the problem. Replace or adjust the ball, or raise the float arm.

The tank won’t fill

There are several reasons a toilet tank won’t fill and accordingly, a few different solutions you can try to fix the problem:

• No water supply: check the supply valve for the toilet fixture, as well as to the property. If your water is on, the problem may be with the pipes supplying the bathroom.
• Low water pressure: this is usually due to a water pump failure or a clogged pipe.
• Broken trip lever: the connection between the handle and the inside of the toilet tank is broken and needs repair or replacement.
• Fill valve needs adjustment: usually, this can be adjusted with the control screw or valve clip to allow more water into the tank.
• Malfunctioning float ball or arm: these parts can be adjusted or replaced to restore the proper fill process.
• Cracked toilet bowl: this can result in water leaking and eventually, massive water damage. Shut off the water supply to the toilet and call a plumber immediately to replace the toilet.

If you have problems with your toilet and can’t fix them yourself, we’re happy to make a service call to help. Call Sanitary Plumbing at 212-734-5000, or use our easy online form to schedule an appointment.